Disappearing Damsels! Help!!

[lcayres]

Hi all,

My tank is a 12 gallon nano-reef. I have various snails and hermit crabs. Many types of corals (ricordia, zoos, kenya tree, mushrooms, etc) and a sponge. I recently learned (I am out of town, I know terrible to leave the tank in the hands of someone else) that my two damsels disappeared, they were a yellow-tail and a fiji blue devil. They got along fine and never fought. They lived harmoneously together in my tank for ~2 months. My tank has been up and running for 7 months now. I have had a coral banded shrimp and a lawnmower blennie die in it, obviously I did a water change and removed their corpses immediately...but they did not disappear like these damsels. They apparently disappeared one night, both of them.

I recently added a sponge, feather duster, & kenya tree piece to my tank (about 1 week before the disappearance). I suspected a bristleworm of sorts and sent my boyfriend (a nano-reefer as well) to do a water change and to give my roommate (taking care of the tank with explicitly written out instructions) a Petco-bought bristleworm trap. She says she used it and nothing came up. Any other suggestions?? I know its difficult with me not being there, but I can have my boyfriend &/or roommate do any nessecary checks, tests, etc. if someone is willing to let me know what I should do. Thanks so much!!

[scottfaulkner11]

is it possible for them to have jumped out? or for the roommate to have found them dead and claimed they disappeared? Its very unlikely for them to just "disappear" like that haha. especially if someone had seen them one night and not the next. if its an open top, another experience i have had is a cat stealing the fish, maybe? As for the bristleworms... i highly doubt that could be the issue seeing as how you would have to have a several huge ones to devour 2 fish in one night.. cant imagine it. Is it possible that they are hiding somewhere that your roommate is not used to being aware that they may do that? If none of that helps you im clueless haha

[scottfaulkner11]

also you said you had a coral banded shrimp, did you put another one in? Occasionally those can be agressive and eat the other fish, but it is rare. Another problem i have encountered before similar to what you are saying are mantis shrimp. Those can be a pain, and you will need to trap them if u wish to remove them. ive had several come along as Lr hitch hikers before

[lcayres]

There is a top to the tank...I'm almost 90% positive they didn't jump out. My cats watch the tank but since there is a top they have never tried to get the fish...and are declawed (which I don't know if that matters or not). I'm sure my roommate would tell me if my fish died because she has told me before when things didn't look right with my blennie (and he died the next day). I doubt they are "hiding" because my boyfriend did a water change and moved the rocks around a bit to make sure they weren't in/under them. I am at a loss...could it have been they died naturally and were eatten by hermit crabs over night?

[lcayres]

I do not have another coral banded, I wasn't all that sad when she died because she always pinched at the corals and fish. :-\ How do I get rid of a mantis shrimp? Could it do this damage to the fish in one night?

[scottfaulkner11]

hmmm... about the coral banded, good i wouldnt get another haha. what did she bait the bristleworm trap with? if she put some kind of frozen food like mysis or the like in the trap and turned the lights out and checked it in the morning it shouldve had something.. if there was one in the tank. with the mantis shrimp, yes the can kill fish pretty easily if they get ahold of it. now before jumping to any conclusions about that, yes they could have died from some other cause and then be eaten in one night by the various life that is in the tank, visible and not.the hermits will eat away at stuff like that, but only if its dead or dying. the thing that strikes me though is that you had not one, but two gone in one night... im stumped on that. and if youve got a lid then u shouldnt have to worry about the cat haha. especially if its declawed. i really dont know what it could be though. you could try to view the tank at night though and see if u have any bristleworms or mantis shrimp come out, to do that just keep some light in the room just low enough to view the tank, like a lamp across the room or even a flash light with your hand covering a largeportion of the lens.. too much light will run them off. if u have one of those led keychain lights or something thatd be perfect. but again, to me it sounds kind of like a mantis shrimp. those are an easy fix if uve already got the trap, just bait it with meaty food.

[scottfaulkner11]

and the lawnmower blenny most likey died bc of the tank size. a large portion of their diet is from the snacking they do all day long from the environment. So unless you had something to sustain that type of eating for them it would be very hard to keep in a 12g i imagine. something very cool to put in their would be a yashia goby and candy red pistol shrimp pair. theyre pretty neat and they for a symbiotic relationship so they stick together almost always haha

[leebca]

Can't help more than what others have mentioned, however that size aquarium should be devoted to a reef tank, and not include any fishes at all.

[mr_brix]

hey it happened to me too i had a green chromis disappeared at night and the second night my diamond damsel i tried to search for it in my 72gal tank i moved all the rocks and flip it to see if its underneath but i didnt find it.. and i watch my tank at night for 2 days and did not find any sign of preditor... then after a couple of days my damsel appeared dead and the chromis never did.. im wondering why i didnt see it when i moved all the rocks at that time.. then 2months after one of my chromis disappered and i did a search and i found it underneath a separate rock and i did an autopsy the eye ball is gone but the whole body is fine.. and before the disapearance all of my fish a looking good with no sign of sickness...