Table of Contents:

May 2005 Edition Introduction: Introduction to May 2005 RHO By: Scott Zachow & Gene Schwartz Cover Photo: Antennarian's By: Anthony Calfo Equipment Review: How About A Little Bubbly? Protein Skimmers By: Scott Zachow Main Atrraction: Be A Host To Your Anemone By: Ronald L. Shimek, Ph. D. Featured Member: Make It Small-Sized By: Elmo18

Antennarians – Frogfish By: Anthony Calfo

Cover Photograph Antennarians – Frogfish By: Anthony Calfo Photo by Anthony Calfo Frogfishes and Anglers are found circumtropically, but are commonly imported from the tropical Atlantic, Hawaii and the Indo-Pacific for the aquarium trade. Most are collected small and have modest adult sizes ranging from 3-6" (7.5-15 cm), although a few popular species can approach or exceed 12" (30 cm). Live fishes and shrimp are the standard fare offered and accepted. Better candidates will accept frozen meaty foods in time (teasingly offered with forceps or a skewer). Few common names are needed for this group when the earliest ones are so befitting; Antennarian’s are called Anglerfish for their specialized "fishing apparatus" used for luring unsuspecting fishes, and Frogfishes for their large mouths and squat amphibian-like appearance. In popular literature, the Antennarians imported for the aquarium trade are perhaps best called "frogfishes". The name "anglerfishes" is generally ascribed to the deepwater denizens of the family with truly exaggerated lures. With little consequence or meaning, I'll favor the term "frogfishes" here and rest in the knowledge that its always best to cite species by scientific name whenever possible instead of or in addition to common names. Selection The first step to finding a healthy frogfish is just like preparing for the acquisition of any other aquarium specimen: know and understand their natural habitat and behavior first. Most frogfishes are benthic creatures that spend their entire lives on hard substrates (excluding the adult surface-dwelling Sargassum Histrio). By any measure, they are remarkably inactive creatures. As such, we must pay close attention to other aspects of behavior and carriage when evaluating new imports for purchase. Healthy lophiiform fishes are "bright" in appearance and behavior. Their eyes should be clear and aware, shifting to follow you and other stimuli that come near them. Respiration should be slow and deliberate. You’ll notice that their gill slits are very discreet in an effort to conceal their presence as living aspects and ambush predators on the reef. Closing one gill while pumping the other, in contrast, is a possible sign of gill parasites. Unless recently fed, these fishes should respond positively to the introduction of food or prey by stalking or "angling" for them. If irritated by imposed stimuli, you can expect them to "walk" away… crawling across the seafloor with modified pelvic fins that resemble feet in form and function. Although it is their nature and habit to be inconspicuous… indeed cryptic… they will break formation and evade your exploratory net handle, gentle stick, or hand in the tank at some point. Complete inactivity may indicate a stressed or sick animal. Newly arrived specimens should be permitted to settle in for some days (a week or more ideally) before taking them home for quarantine. It may be necessary or appropriate to offer your merchant a deposit to hold such fishes during that time. Patience in moving recently airshipped or otherwise transported specimens will go a long way towards lower rates of morbidity and mortality. Care should be taken to transfer all lophiiform animals in slow, deliberate motions, and not exposing them to the air where they may gulp in the atmosphere, or suffer under the unnatural weight of their gelatinous, scaleless bodies above water. Rest assured that they are slow and predictable enough to easily catch by coaxing them to walk along ("pushing" them) into a submerged plastic bag or specimen container. Wrangling and moving frogfishes with nets can cause serious and unnecessary damage to delicate tissues. The specific coloration of individuals in this most cryptic family of reef creatures means little to nothing for identifying their health or even species. Their visage is ever-changing and adaptable, particularly with regard for coloration. The substrate upon which they rest or migrate to naturally is highly influential on the colors they show. Some species are especially variable and will match the shades of numerous benthic reef growths in colors of red, yellow, black, orange and much more. They may even appear to mimic textures like pores and exhalent openings in sponges. And we can find examples of species with physical extensions that resemble seaweed! All of this magnificent evolution testifies to their lifestyle as an ambush predator. You will also notice that frogfishes have strategically upturned mouths – a clear indication of their lifestyle. They sit on the seafloor camouflaged, braced or wedged with their frog-like feet… and wait. When potential prey draws close enough to be of interest, the famous fleshy lure-tip (the esca) is utilized to draw them nearer. Where body coloration alone is useless to differentiate between like resembling species of frogfish, the esca can often be distinguishing. Some species have esca that have evolved to be wormlike, while others may remarkably resemble a small fish. If bitten off, then fleshy esca can indeed be regenerated after some months. The lure-pole of an anglerfish is, in fact, a modified dorsal fin spine (called the illicium). Much like a fishing pole, some lophiiform fishes angle with the extended tip of this spine like a fisherman angles for sport. Unlike a fisherman, however (well… a sober fisherman, assuming such a creature exists), anglerfish keep their lure very near to the mouth. When prey finally makes it to within striking distance, they draw them in with a sudden and convulsive suction produced by a rapid expansion of their mouth. Anglerfishes can expand their mouths into remarkable caverns by a ten-fold increase in size. The action takes mere milliseconds and is one of the fastest recorded movements in the animal kingdom (lagging just behind the lighting speed of the opening of a beer can by the aforementioned thirsty fisherman). This strategy can be described as aggressive mimicry (the use of a lure by frogfishes, that is… not the beer drinking by a fisherman). Care Habitat is one of the first things a keeper needs to address with new fishes. As mentioned before, most frogfishes inhabit rocky environments, but many do indeed occur on soft sandy substrates and flats. There is of course the pelagic Sargassum species too (provide natural Sargassum seaweed or a like substitute both floating and anchored for display). From all niches, though, the lophiiforms tend to favor slower water flow and quiet environments. They can regularly be spotted in the wild near piers and seagrass beds. Where modern reef aquariums need at least 10-20X water flow per hour in the aquarium, keepers of these fishes need not exceed the range. Larger specimens producing larger amounts (volume and particle size) of waste will benefit from high water flow to process solid matter more efficiently. Naturally, heavy bio-filtration will be needed as with any predaceous fishes for the copious amounts of nitrogenous matter generated by large, heavy or messy feedings. Employ over-sized trickle/wet-dry filters and/or fluidized bed filters here. The decor of the aquarium is a subject or many possibilities and great fun with frogfishes. Their proclivity to change color dramatically and rapidly is legendary. Their talents at mimicry challenge a keeper to provide ever-more interesting colors and textures to the artifacts in the aquarium with hope of seeing even more impressive displays of camouflage. Colored sponges in the wild are some of the very best backdrops for which to view frogfishes against. For their challenging nature in aquariums, however, live sponges are not recommended for most aquarists; they can be quite noxious and even toxic! Artificial ornaments are taken as perches just as readily as natural substrates in the aquarium. Some aquarists like to have great fun with swapping out various colored rocks and ornaments to the see the evolving show of color that unfurls with each change of venue as the fish moves around the tank. Provide some significant measure of hard substrate in the aquarium for essentially all in this group. Live seagrass displays (Thalassia or Syringodium) make outstanding habitats for most all species in this group overall. Foods/Feeding/Nutrition and Compatibility Interestingly perhaps, I lump "compatibility" in with "feeding" coverage here. This is done for some very practical if not obvious reasons with this predatory family. The rules that apply to both are very simple: if it can be eaten whole, it will… and if it can’t be eaten whole, it might be attempted anyway! Ahhh… right. These are simple rules to follow. And forgiving the slight exaggeration, you will do well to heed this warning, and your fishes will live longer for it. Antennarians will eat fish and most any motile invertebrate. Shrimps and small bony fishes are favored prey. Even members of their own species are fair game! The stories and legends of what some frogfish have eaten is amazing: with seabirds, lionfish and inflated spiny puffers, and more. And while tankmates clearly too large to swallow whole generally will be ignored, it’s best instead to keep only one frogfish per tank and perhaps in isolation as a species-tank. As mentioned previously, numerous active community fishes if not predated may in turn nip or harass lophiiforms. We should not avoid the toothy predators alone here, but even the smaller or less predatory fishes that naturally graze upon the reef are a calculated risk; they can mistake the lophiiform animal for part of the living substrate and rasp dangerous wounds into its flesh as if it were encrusted benthic fauna! Without traditional scales, venom, spines or other exaggerated means of defense, the soft-bodied Antennarians are fairly vulnerable at large. One means of defense employed is to quickly inflate their stomachs with water to foil attempts by some predators to inhale them. Unfortunately, the strategy is useless against predators with large enough mouths or those with larger teeth like puffers and triggers. There is also the concern of territoriality between frogfishes. Although some will tolerate each other, often times they demonstrate intolerance except briefly during breeding season. You can expect the same intolerance of other fishes in aquaria in most cases. Keeping frogfishes in species tanks also makes feeding time much easier with these very slow predators. As one can imagine, active feeding fishes will simply steal small live feeder shrimp or fishes away before the lumbering frogfishes can get to them. Some individuals after acclimation will take prepared foods while others are rather slow to wean off of preferences for live prey. Most however, can be trained in time to take dead meaty foods from a feeding stick. And much like other commonly "stick-fed" predators (eels, octopuses, mantis stomatopods, etc.), lophiiforms will demonstrate individual preferences for how they "like" to be fed. Some will respond to a moderate to vigorous tease of killed prey dancing by the movement of your hand on the stick, while others show irritation to excess stimulation and may even require repetitive drops of food chunks through the water column sans stick. Experimentation with the delivery of dead or prepared foods is required on a specimen-by-specimen basis. Try to always offer saltwater aquarium inhabitants foods of marine origin. Few freshwater or terrestrial foodstuffs are adequately nutritious to constitute any significant part of a marine animal’s diet. Even prepared meats of marine origin are deficient in some ways if cleaned, gutted or otherwise rendered incomplete. Whole prey are best (head, guts, legs, fins, wristwatches, whatever… intact). Shrimp, krill, and silversides are common fare for frogfishes. HUFA rich supplements are recommended here too to soak thawing foods in. For live foods, be sure to maintain a proper holding tank of prey as if in quarantine, and never feed live prey that has been only freshly acquired for fear of transmitting an infectious disease. Keep feeders for a minimum of 2 weeks to reduce the chance of a pathogenic transmission. It would be better still to maintain your own breeding colony of live-bearing mollies, for example, that are brackish or saltwater tolerant and can be gut-loaded with nutritious foods before being offered as prey. Avoid freshwater goldfishes as a staple food item (nutritive concerns) or un-quarantined saltwater baitfishes (disease risk), but rely on killed prey (frozen meats) to exclusion instead if you must. Small live ghost/grass shrimp (Palaemonetes) are also quite good food items. And true to form with all of this hype about frogfishes being voracious predators, they can be observed angling with their lure day or night! Some have suggested that nocturnal prey can sense the feel or vibration of the lure at night, but at least one species of frogfish has been documented to contain bioluminescent bacteria in its lure - lending the frogfish full-time feeding opportunities. Whether you opt for live or thawed frozen foods for your frogfishes, be very mindful of prey size: items that are too large may still be accepted but nonetheless are dangerous. Proffer no items larger than 20-30% of the animals total body size; smaller is always better. Oversized prey can harm or kill greedy lophiiforms by taking too long to digest. It will hinder respiration and, less commonly, may build up gasses in the digestive system from decay that causes the animal to struggle with buoyancy issues. Much like anemones, which also get commonly overfed with food chunks that are too large, the animal will often regurgitate the meal later – perhaps after the lights go out and causing attrition if repeated habitually, despite the keepers best intentions. Most marine fishes fare better with small frequent feedings. Frogfishes will tolerate only a few hearty feedings weekly with extra offerings to the smaller and younger specimens. Photo by Anthony Calfo Reproduction Spawning and reproductive activity in frogfishes is fairly well documented and frequently observed. In fact, they appear to be one of the earliest species observed to reproduce in modern aquaria. Frogfishes are even commented upon in classical history by none other than Aristotle, 344 B.C.! Like so many other marine fishes, it is the rearing of their larvae that has been so elusive to aquarists. Oftentimes, these events in aquaria occur soon after the import of a gravid female. Unfortunately, fertilization of the eggs is external, and fruitless without a male of course! Dimorphism is not apparent in most species – the girls and boys generally look alike... to us humans at least. Reproductive females become quite swollen and egg-laden just prior to copulation (mere hours/days prior). Some frogfishes move to deeper waters to spawn, but overall they are regarded as relatively shallow water denizens of the reef. At least Histrio, the Sargassumfish, has been observed to spawn year around with no apparent season or reproductive cycle. Courtship occurs by day, although the spawning event itself may occur day or night. Males chase the gravid and clumsy females by "nudging" them along and above the seafloor just prior to a brisk dash by the pair to the surface for egg release and subsequent fertilization. Spawns are comprised of gelatinous rafts or ribbons that usually float. Both Antennarius and Histrio have been observed to spawn in aquariums. We have good reason to ultimately be hopeful of rearing frogfishes successfully in aquaria as the eggs are large and the planktonic stage for larvae in some can be fairly short (21 days, Thresher 1984), although the range in this family extends as far as 2 months or more. Although broadcast spawns are the rule in this group, some demersal strategies have been observed with the parental care of egg clusters upon the flanks of the adult frogfish. Its best to separate frogfishes in aquaria after a spawning event as males can become aggressive or belligerent. Frogfishes by nature are solitary animals. Disease and Health Issues On a scale of susceptibility to disease, frogfishes rank on the weak side; they are rather prone to external parasites, even beyond the common Cryptocaryon and Amyloodinium infestation. For the treatment of external parasites, use copper strictly and with close supervision on these scaleless fishes. Maintain therapeutic levels diligently with small daily doses, and be sure to monitor its use with a copper test kit. Formalin based medications have also been shown to be helpful here. With good water quality and regular feeding, bacterial infections are uncommon in this group. Yet, new imports may show such symptoms or receptive wounds from the stress of capture and repetitive, abrasive contact with the walls of the shipping vessel. Treatment in quarantine with broad-spectrum antibiotics is effective on such fishes. And lastly, issues of gas accumulation that lead to swimming difficulties are observed in frogfishes. Although not immediately perilous, they are a source of great duress for the clumsy swimming or struggling victim (difficulty feeding, avoiding features of set-up and hardware like intakes and overflows, etc.). The two most common causes are gulping air from being inappropriately removed from water, or from being fed food that’s too large. The former cause can often be remedied with a (latex) gloved hand in the water grasping the fish and gently massaging it or harnessing a wriggling attempt at escape; orient the mouth of the afflicted upwards with the intent that stimulation will burp then air free. Overall, issues of disease and health among frogfishes and walking batfishes are relatively uncomplicated and can easily be tempered by good selection, proper quarantine and dutiful husbandry of specimens in species tanks. Summary This group at large can make very interesting and worthwhile aquarium guests. Their needs are somewhat specific if not challenging (hand or live feeding, large bio-filters, exclusion from community tanks), but their merits abound. They are fascinating physically and behaviorally, and occur in seemingly countless and changeable colors and textures. The potential for captive reproduction in Antennarians is very plausible for aquarists too. Seek specimens from the nearest points of collection (Florida and Hawaii for American aquarists) to reduce the stress of import on captive specimens. Anthony Calfo Back to Current Edition Table of Contents View Printable Version

Be A Host To Your Anemone By Ronald L. Shimek, Ph. D.

Main Attraction Be A Host To Your Anemone By: Ronald L. Shimek, Ph. D. Why Not Keep An Anemone? It would seem that keeping a host sea anemone should be the easiest thing in the world for an aquarist. After all, such animals are offered for sale in every local fish store and, "Hey, what could be so hard about keeping one?" Well, the answer to the last question is, "Just about everything." To forestall the worst possible outcomes, in this short article, I hope to provide you with some information about how to care for one species of these fascinating and beautiful animals. Host sea anemones present a real quandary for most aquarists. They are ecologically very important and with only one exception they effectively cannot be propagated in captivity. Furthermore, in natural situations, populations do not recover at all well after harvesting. Generally, when a host anemone is harvested for sale in the aquarium trade all of the associated animals: symbiotic fishes, shrimp, worms, and other crustaceans, die. They can’t migrate to some other anemone, as these are either full to capacity with their own symbionts or the nearby anemones have already been harvested by a collector. Once an anemone is harvested, the reef where it was changes drastically. Research indicates that it may decades or longer before a replacement anemone is likely to be found there. Today's coral reefs are severely threatened by global warming. In the past 30 years, over 20 percent of coral reefs have disappeared and most of the rest are damaged. Removal of such ecologically important animals as host anemones accelerates such change. Nonetheless, the economic law of supply and demand ensures that the harvesting of host anemones will continue until we either run out of anemones (which has happened in numerous localities), or such collection is outlawed. The image of a sea anemone with its symbiotic clownfish is one of enduring icons of coral reefs. It appears that aquarists will be purchasing these animals for their aquaria as long as there are anemones and boxes of water to put them into. This means anemones will be purchased, and within short order, most of them will die. Given that they are effectively immortal in nature, this is inexcusable; especially as it is relatively easy to keep at least one species, the bulb-tipped anemone, known to scientists as Entacmaea quadricolor. Some Generalalities Sea anemones are animals, not some weird type of marine plant. As a result their care is more demanding and involved than is the care of a daisy in a windowsill planter. To care for them properly, one needs to know a bit about them, and a bit about how they live. Biologists classify sea anemones as being in the Class Anthozoa of the Phylum Cnidaria. There are several thousand species of sea anemones, but in this article I will concentrate on Indo-Pacific Host sea anemones. A generalized sea anemone is polyp; a baglike animal having tentacles and a mouth at one end. he opposite end, "the pedal disk," is specialized for attachment. Muscular and flattened, it has a glandular epidermis that secretes sticky mucus, which helps the animal grip the substrate. Anemone body walls consist of three layers: a non-cellular middle layer of material called "mesoglea" sandwiched between two tissue layers. The outer tissue layer is called the "epidermis," while the internal one is called the "gastrodermis." In most sea anemones the mesoglea is thick and fibrous and it forms a rugged and durable sheet of proteinaceous material to which both the gastrodermis and epidermis connect (Koehl, 1976). The interior of the bag is the gut, also known by the jargon terms of the coelenteron or gastrovascular cavity. Gut works equally well, and is a lot easier to type, so I will use it here. Figure 1. Sea Anemone Anatomy (Modified from Fig. 4.35, Kozloff, 1990). Incomplete septa do not reach the pharynx, and septal perforations allow water to move between the gut compartments during contraction or deformation. The simple anemone body plan, however, has been significantly altered by natural selection. No longer is the mouth just a simple "hole" opening to the inside, rather the inner edges of the mouth fold down and continue internally as a tubular projection, called the pharynx. Additionally, thin tissue sheets, "septa," extend from the outer body wall toward the center of the cavity. Many of these fasten to the pharynx. These septa divide the gut into a great many compartments at the top of the animal but all of them are open to the central core at the bottom. If you were to cut across an anemone parallel to the substrate, the inside would be seen to be subdivided into many narrow "pie slice-shaped" sections. These septa also are associated with the tentacles; septal walls are continuous with the sides of the tentacle base. Consequently, the number of tentacles normally equals the number of septa. Continuing with the inside story, the center edges of the septa, below the level of the pharynx, often are extended out into long, threadlike, internal strands called septal filaments. These are often heavily laden with nematocysts and may be used to finish killing any ingested prey. Natural Born Killers Nematocysts, used by all cnidarians to capture their prey, are tiny proteinaceous capsules secreted by some of the animals' epidermal cells. The capsules' thick walls enclose fluid-filled cavities under immense pressure, about 176 kg/cm2 or about 2500 lb/in2. Capsular contents may be toxic venoms. A coiled thread extends into the cavity. There are about 30 different types of nematocysts, and some of them have hollow threads, which allow the capsular contents to exit through them and enter the prey. Others contain simple threads or glues to entangle and immobilize prey. (Hesslinger and Lenhoff 1988; Russell and Watson 1995; Thorington and Hesslinger 1996). Additionally, nematocysts are often "tuned" to the type of prey - so that if the anemone eats fish, its nematocyst venom is specific to vertebrates and won't particularly affect shrimps or squids. Such vertebrate-specific venom will, however, affect aquarists. Figure 2. Diagram of a nematocyst. Left. Showing the position in a epidermal cell with a nerve cell process entering the epidermal cell to contact it. Right. Internal structure of the nematocyst. Figure 3. Nematocyst Action (Modified from Ruppert et al., 2003). The sequenced of events, from top to bottom, occurring in nematocyst discharge. This whole sequence can take place within 1 millisecond. Normally anemones capture their prey using tentacular nematocysts. The septal filament nematocysts may have another function. Once a prey item is ingested, it is wrapped in septal filaments, and their nematocysts likely hold the filaments tightly to the prey, creating small volumes between the filament and the prey where enzymes secreted by nearby cells could be confined for the digestion of the prey (Baumann, 1995). Additionally, the cells of the gastrodermis ingest small fragments of the prey and much of the digestion occurs in those cells (Ruppert et al. 2003). Figure 4. Nematocyst aggregations are visible as the dark pink colored lines in these tentacles of a temperate anemone, Cribrinopsis fernaldi. Sea anemones lack muscles, instead they contain many epidermal and gastrodermal cells which contain contractile fibrils and, like muscles, are able to contract. The contractile elements occupy much of the cell and these cells approach the capabilities of true muscles in their abilities. Under extreme conditions, bands of these muscle-like cells in the septa can contract and flatten even the largest sea anemone into a thin pancake of tissue. Contractile tissue bands are also found around the column’s base and as sphincters around the mouth. Other smaller ones are found on the tentacles and along the sides of the column. Sea anemones are covered, both internally and externally, by small, beating, hair-like cellular projections called cilia. Externally, they generate small water currents that move particles off the animal. In the gut, the currents they create circulate fluid through the gut. There are also one or two densely ciliated tracts called "siphonglyphs" that run from the outside to the inside down the corners of the mouth. These tracts pump water into the animal ensuring that the internal contents don't become stagnant. These ciliary currents are also the only way fluid can get into a contracted animal to re-inflate it. Such inflation may take over 24 hours. Anemones possess simple networks of nervous tissue running through the epidermis. They lack true sensory organs, but their surfaces are covered with small sensory cells. They have nothing resembling a brain, and cannot learn. Nonetheless, many sea anemones have a few stereotyped behavioral responses, probably based on a series of simple reflex arcs. Reproduction Sexes are generally separate in sea anemones. The typical reproductive pattern is one where both sexes spawn into the sea where fertilization occurs. Within a few days of fertilization, a swimming motile larva called a planula is formed. Depending on the species, the larva may or may not feed. Eventually the larvae will metamorphose into a small sea anemone and take up existence in the benthic environment. Asexual reproduction is common in some anemones, including the bulb tipped anemone, Enatacmaea quadricolor, which may reproduce by splitting into two or more clonal descendants. Such cloning is absent or very rare in other host sea anemones. Host Anemone's There is a considerable diversity of form and biology "hidden" in the common name of "sea anemone." This is really a group where "one size does not fit all" and, unfortunately, aquarists tend to forget that fact. The several types of Indo-Pacific host anemones are amongst the hardest of anemones to keep. The difficulties of care stem from different reasons in the different species. There are 10 species of anemones that will act as hosts to clownfishes. These are the adhesive anemone, (Cryptodendrum adhaesivum), the bulb-tipped anemone, (Entacmaea quadricolor), the beaded anemone (Heteractis aurora), the Sebae anemone, (Heteractis crispa), the Ritteri anemone (Heteractis magnifica), the malu anemone (Heteractis malu), the long-tentacled anemone (Macrodactyla doreensis), the gigantic carpet anemone (Stichodactyla gigantea), the haddoni or green carpet anemone (Stichodactyla haddoni), and Merten’s carpet anemone (Stichodactyla mertensii). Common names change with the wind direction, and scientific names are applied almost haphazardly by dealers, so don’t trust any identification unless you can verify it yourself. The long-term survival rate (where long-term means a year or more) in captivity for most of these species is essentially zero. Experienced hobbyists may be able to maintain sebae anemones, long-tentacled anemones, and some of the carpet anemones for extended periods; however, about the only anemone a novice reef keeper stands a chance of keeping alive is a bulb-tipped anemone. Consequently, I will focus on the care of this species. Basic Physical Requirements Sea anemones are simple animals; they lack any way to significantly vary or regulate their internal environment. All such animals are dependent upon the water quality of their environment for their well-being. They must have more-or-less perfect coral-reef water conditions. The water must have oceanic salinity of 35 to 36 parts per thousand and temperatures from 27°C to 29°C (about 81°F to about 85°F). The addition of strontium and other similar pollutants should be avoided. Water movement is a necessity; however, the acceptable force, direction, and duration of currents may vary and should be experimented with. Dietary Requirements Host, and many other, anemones have zooxanthellae. People tend to believe that animals with zooxanthellae either don't need to be fed or fed very much. This is definitely NOT the case. Zooxanthellae may provide nutrition to their host, but in turn, they need many chemicals, such as nitrogenous compounds, available only from their host’s digestion of food. Additionally, the anemones acquire significant and necessary mineral and proteinaceous materials from their diets rather than from their zooxanthellae. Host anemones need to be fed, and for good health often need to be fed a LOT. After good water, the most important thing hobbyists need to provide is the proper diet. Sea anemones are slow-moving predators that wait until they contact their prey contacts them, but then they must kill it rapidly. Sea anemones are active discriminatory predators which maximize the likelihood of predatory success by choosing an appropriate microhabitat to encounter their mobile prey and by having the appropriate toxin to kill it. As you might expect, there is a correlation between the type or behavior of their prey and the morphology of the predator. As an example, Entacmaea quadricolor, projects its relatively large tentacles up off the bottom where they might encounter swimming or planktonic prey. Additional factors in dietary specificity include the nematocyst venoms used to capture the prey and the enzymes necessary for digestion. These are metabolically expensive. Natural selection acts to eliminate the production of enzymes not specifically necessary for capture and digestion of a predator's normal prey. As a consequence, anemones that eat fish in nature may not be able to eat shrimp in an aquarium, and may not even perceive of shrimp as food. The appropriate diets for individual anemones should be determined by systematic testing of various potential foods, such as diced fish or whole shrimp. While it is broadly possible to predict what the diet will be differences within subpopulations may lead to specialization for alternative prey. Fortunately, Entacmaea quadricolor appears to be a bit of a dietary generalist, thriving on fish and crustacean prey, thus many foods are acceptable to it. When feeding, the whole prey item should be fed. Predators get important and essential nutrition from all parts of their prey including the guts and internal organs. Once an acceptable food has been determined, the appropriate volume and schedule must be determined. The aquarist should gradually increase the amount of food to find out how much will be taken at one time. With only one opening to the gut, anything that is undigested has to come out the mouth, too. The time to regurgitation of undigested material; if any is regurgitated, should be eaten. Then feed again on the day following the regurgitation. If no obvious expelling of food residue occurs, feed again after two or three days. Probably as minimum, the animals will need to be fed two or three times a week to remain healthy. Habitat Requirements Being zooxanthellate, bulb-tipped anemones need light, but as long as they are well fed they don't need exceptionally bright light and will do well in a moderately-lit aquarium. Much more critical is providing an acceptable substrate. The behavior responsible for habitat selection is hard-wired into these animals, and they have little plasticity in such behavior. Simply put, they do not have a nervous system capable of learning to live in a new type of environment. Without the appropriate habitat, the animal will be stressed and prone to move to find an appropriate habitat. A moving anemone is an unhappy anemone, and will eventually die unless it can find a place that it can call home. Entacmaea quadricolor are naturally found in crevices or holes, with only their tentacle crowns or oral disks visible. An acceptable home for this species is a small depression that has rocks on all sides where the animal can contact them with its sides. With this species, the sides of the animal appear need to have contact with rocks, and probably calcareous rocks, for the animal to remain immobile. Figure 5. Entacmaea in a crevice in a home aquarium. Such a habitat seems to satisfy the animal’s need for a hole or “crack in the rocks” within which it will live. One might be excused for thinking it would be possible to simply train the animals to live in a different place, or to possibly accept alternative foods. Only to small extent is this true; it is unlikely an aquarist can provide the same diet the animal would have in nature. If the animal is to survive, it will need an acceptable, if not identical, food. However, the aquarist had better do their best to come as close to it as they can or the animal will not get sufficient nutrition. Habitat variations seem to be a lot less acceptable. For the anemone's good health, aquarists must attempt to recreate the appropriate habitat, and must provide an appropriate food. Such is the price you must pay for a happy sea anemone. Good habitat and good food will result in well-maintained animals. In turn this commonly results in asexually produced clonal individuals. br /> The basic principle of attempting to duplicate or provide a habitat that approximates the natural environment while providing a natural diet is fundamental to all good captive animal husbandry and must be practiced for successful maintenance of most of the animals in the marine aquarium hobby. Ronald L. Shimek, Ph. D. References Cited: Bumann, D. 1995. Localization of digestion activities in the sea anemone Haliplanella luciae. Biological Bulletin. 189: 236-237. Dunn, D. F. 1981. The clownfish sea anemones: Stichodactylidae (Coelenterata: Actinaria) and other sea anemones symbiotic with pomacentrid fishes. Transactions of the American Philosophical Society. 71: 1-115. Fautin, D. G. and G. R. Allen. 1992. Field guide to Anemonefishes and their host sea anemones. Western Australian Museum, Perth, Australia. 160 pp. Gosselin, L. A. and P-Y. Qian. 1997. Juvenile mortality in benthic marine invertebrates. Marine Ecology Progress Series. 146: 265-282. Hesslinger, D. A. and H. M. Lenhoff. (Eds.): 1988. The biology of nematocysts. Academic Press. San Diego. 600 pp. Koehl, M. A. R. 1976. Mechanical design in sea anemones. pp.23-31. In: Mackie, G. O. (ed.) 1976. Coelenterate ecology and biology. Plenum. New York. 774pp. Ruppert, E. E, R. S. Fox, and R. D. Barnes. 2003. Invertebrate Zoology, A Functional Evolutionary Approach. 7th Ed. Brooks/Cole-Thomson Learning. Belmont, CA. xvii +963 pp.+ I1-I26pp Russell, T. J. and G. M. Watson. 1995. Evidence for intracellular stores of calcium ions involved in regulating nematocyst discharge. Journal of Experimental Zoology 273: 175-185. Thorington, G. U. and D.A. Hessinger. 1996. Efferent mechanisms of discharging cnidae: I. Measurements of intrinsic adherence of cnidae discharged from tentacles of the sea anemone, Aiptasia pallida. Biological Bulletin. 190: 125-138. Back to Current Edition Table of Contents View Printable Version

Featured Member - Make It Small-Sized By: Elmo18

Featured Member Make It Small-Sized - Elmo18 Tank Size: 18"L x 18"W x 21"H outer dimensions ~roughly 27 gallons when filled. Sump/refugium is a food-safe grade bin holding about 10 gallons. Lighting: 1x 250 watt MH –XM 10k SE bulb run on ARO Electronic Ballast 3x 28 watt PC 03 actinics run on 3x ARO Nano Ballasts Metal halide comes on at 12:00 pm, turns off at 6:00 pm. Two side PCs come on at 10:00 am, the middle PC comes on at 11:00 am; two side PCs turn off at 9:00 pm and the middle PC turns off at 10:00 pm. Filtration: All filtration are either biological or chemical. I employ a Deep-Sand Bed (DSB) starting with about 4" of fine aragonite sand. I chose to use Southdown sand for this. Roughly about 40lbs of Premium Fiji rock help with natural filtration. I soak carbon in my sump/refugium continuously (24/7) and replace it every two weeks. Circulation: For the return back from the sump to the display tank, I use a MAG7 plumbed via PVC. I also employ a closed loop via an Iwaki MDRLXT20 pump. The intake for the closed loop is through a 1" bulkhead, and outputs via 2 x ¾" bulkheads. This gives roughly a 24-27x total turnover rate. Current Fish: Spawning pair of Premnas biaculeatus (Gold-stripe maroon clowns) Pair of Amphiprion sandaracinos (Orange-skunk clowns) Corals: The tank is setup with a concentration on small-polyp stony corals. I do have a few corralimorphs and a couple long-polyp stony corals, so I do call it a mix-garden tank. Here are some corals that I have in my tank: Acropora sp. Montipora sp. (digitate and scrolling/plating forms) Discosoma sp. Fungia sp. Echinophyllia sp. Briareum sp. (green variety of star polyps) Current Water Parameters: Specific Gravity = 1.0255 Temperature = 79-81 degrees Fahrenheit Alkalinity = 10 dkh Calcium = 400 ppm Nitrate = 0 Phosphate = 0 Magnesium = 1250 ppm PH = 8.0 – 8.2 Mainenance Routine: Five gallons of water is changed weekly with aerated saltwater mixed overnight Kalkwasser is used for calcium and alkalinity via topoff water Liquid calcium and Baking Soda is used if calcium or alkalinity are imbalanced Fish are fed twice a day Carbon changed out every two weeks; replaced with ½ cup new carbon Chaetomorpha sp. and Caulerpa sp. algaes are pruned as needed Favorite Fish, Coral and Invert: My favorite coral in my tank is the plating Orange/Red Montipora sp. This coral originates from Rocky in Florida. I love the strikingly bright coloration and its fast growth rate. My favorite fish(es) are my mated pair of Premnas biaculeatus. They originate from Jeff’s Exotic Fish via mail-order about four years ago. They are perhaps the most important inhabitants of the tank. My favorite invert is my Lysmata amboinensis, or my Skunk cleaner shrimp. The shrimp originates from Saltwaterfish.com about three years ago. It is fun to watch it scavenge when I bring food, and when it cleans my hands. What Major Transitions Has This Tank Went Through: This system was setup on September 2004 via a tank transfer from my old 75 gallon tank, which had been running for 3 years. All live rock placed into the 27 gallon tank came from the 75 gallon tank. So far no major stumbles yet. However, upon transferring the system, I wanted to remove all corallimorphs from the live rock. Apparently, I missed a few and they are now spreading along the bottom edge of the tank. I may have to trim them when they grow bigger. Another problem I have is associated with my maroon clowns. They are my joy so when I acquire corals, I have to keep in mind that the clownfishes may knock it over. What Drives This Beautiful Aquarium: For me, the inspiration comes from being born in Indonesia. I grew up around fish and coral suppliers in Yogyakarta and Bali. I have never thought of having a freshwater tank when the ocean was there with so many more exciting animals. It is nice to have a piece of my native land in my living room. The animals inside the tank are what’s important as they are a link to back home. Future Plans: I am planning to move the two orange-skunk clowns and place them in a new separate tank. They are not fighting at the moment, but I believe the two species coexisting in such a small tank may hinder spawning of the two. I may also drain the tank at some point and drill holes for another closed loop. The flow is fine at the moment, but when the corals grow and block flow, I believe I need to add additional flow. I attempted to not use any powerheads in such a small tank, mainly because I need all the space I have. In your mind, what is ethical reefkeeping? Ethical reefkeeping means that the health and happiness of the animals in our tanks are most important. I am a proponent of buying captive raised animals so no damage is done to the coral reefs. Keeping the animals healthy in our tanks mean that we must strive to research the animals before buying or keeping one. As hobbyists, we have opportunities to limit damage to coral reefs by trading captive coral fragments and buying captive raised fish whenever possible. Any advice for others? This hobby can get quite expensive in a rapid, short period of time, so my advice is to plan before starting a tank. Skimping on one item later on will cost your more down the road. I started out with Power Compact lighting a couple years ago. Then I bought Metal Halides and Very High Output actinics. While the power compact lighting still serves a purpose for me, if I had bought the metal halides first, I would not have needed to upgrade. My other advice is to be an ethical reefkeeper. Read and research before any animal purchase or donation. Different reef animals need different types of care. If you would like to discuss this feature with Elmo18 or to Congratulate him, please do so in this thread. Back to Current Edition Table of Contents View Printable Version

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