[wozza]

ok got a 4" sand sifting star. from what i read about it before i got i thort it would be fine in my tank but after reading this tread suggestions
i am worred he will not be "ok" in my tank.
i have a DSB that has noticibe life in it, what our your thorghts on this?
cheers james

[charlesr1958]

With a live DSB, I would remove it, it is afterall just going to eat the life that makes your sandbed functional.

Chuck

[Ninong]

In the thread you linked, I suggested that a single 4" sand-sifting seastar would require a minimum of a 300-gal tank with a DSB full of infauna to thrive. Dr. Ron Shimek suggests a minimum of a 500-tank for a single sand-sifting seastar to survive.

"Bad.It is eating the sand fauna. I don't think anyone can maintain one successfully with a functional sand bed in any less than maybe a 500 gallon system. They are really bad news for a lot of worms." -- Dr. Ron Shimek, Sept. 6, 1998

[wozza]

well he is going back to day then!
shame i think they are cool

[Mini_Reef]

I have a sand sifting starfish, in a thirty gallon tank with only about an inch of sand. And I hafta say he's been great! He's the one critter that's been in my tank the longest, just over a year now. Now, granted, he's not 4 inches in diameter, but I'd say he's at least 2".

What's the difference in fauna in a 3-4" DSB and a 1" sand bed?

climbing the side of the tank...


Harder to see in this one, but he's just to the left of the shroom rock

[greenbean36191]

I have a sand sifting starfish, in a thirty gallon tank with only about an inch of sand. And I hafta say he's been great! He's the one critter that's been in my tank the longest, just over a year now.

This is the kind of thinking that makes them so popular in the hobby. However, people don't realize that inverts have pretty weird biology. These stars are theoretically immortal, but in the hobby they rarely last much longer than 2 years. The fact is that they can go about 12-18 months without eating anything before they finally show any outwards signs of ill health. Couple that with a few months of actually feeding off the infauna, and you get the normal captive lifespan.

[leebca]

I refer to them as "Shooting Stars.'

greenbean hit the nail on the head -- these stars can take many moons to starve to death in the aquarium. Most aquarists who own one and it dies many moons later, chalk it up to their lifespan or a specimen that didn't acclimate. But the truth is, it starved to death.

A starving star looks just like a healthy star, until it is near death.

A fair rule of thumb in this hobby -- if you can't feed it, don't buy it.

[Ninong]

Originally Posted by Mini_Reef

What's the difference in fauna in a 3-4" DSB and a 1" sand bed?

It all depends. It depends on the particle size distribution of the sediments and it depends on what you put into your tank (assuming you didn't start out with wild-collected tropical sediments). Smaller size particles will support a wider array of life than large particles. Crushed coral, for all intents and purposes, is useless in this regard.

It you started out like most of us with just dead sand, then a lot depends on what sort of life was available (if any) on your live rock that might choose to live in the sand. If your live rock had been in contact with sediments in the past, it may have some sediment-dwelling critters that might migrate back into the sand once the opportunity presents itself. In general, the sorts of critters that live in the sand are not the same as the critters that live in the rock.

If you started with dead sand and read some of Dr. Ron Shimek's articles, like many of us have, then you might have purchased some of those so-called detritivore kits from one or more online vendors. It you went really bananas like I did, you would have purchased stuff from four different sources, including small samples of live sand and/or live mud from each of those vendors. I also added some Florida Keys live sand that I purchased locally.

Chances are pretty good that you didn't do any of that if you have a 1" sandbed because chances are that if you have a 1" sandbed you don't know what I'm talking about. No offense, just a point.

Don't get me wrong, I'm not saying that everybody has to have a deep sand bed in their reef aquarium or it won't function properly, I'm just saying that a deep sandbed is one approach that some people choose. And people who choose deep sandbeds have to be sure to maintain viable communities of sandbed infauna to keep all those sediments in motion. I will give you a couple of links to articles by Dr. Ron Shimek that explain the workings of deep sandbeds: How Sandbeds Really Work and What Lives in Sand?

Here are two excellent articles by Dr. Rob Toonen on the chemical reactions that take place in deep sandbeds: Part One and Part Two.

There are benefits to be had from a biologically active deep sandbed that are not available with other methods. On the other hand, there are reasons why some people choose an alternative method. Fine particle deep sediments are more difficult to manage in a tank with extremely high flow. And, at the other extreme, you can't keep a deep sandbed healthy with very low flow either.

The reason sand-sifting seastars do not survive long-term in most home reef aquaria is because they run out of suitable food. These animals are programmed to feed on tiny worms, microcrustaceans, bacteria, etc., that live just under the surface of the sand. Once they have consumed all of the available infauna from one spot, they move on to another spot. They are not programmed to feed on the live rock or the glass walls of the aquarium. If you see them on the live rock or the glass, they are searching for food because they can't find any in the sandbed.

The reason that Dr. Shimek recommends a minimum tank size of 500-gallons (with a biologically active >4" DSB) for a single 10cm (4") sand-sifting seastar is because that is the volume of sandbed that he figures can sustain the predation of one of these animals without suffering harm to the sandbed's infaunal populations. If you put one in the sandbed of a smaller tank (say 180 gallons), it may decimate the sandbed infauna, causing populations to crash. You can't eliminate the infauna from the top 1" layer of the sandbed without affecting the populations below. Think of what happened in Yellowstone when we removed the wolves. According to Dr. Shimek, a 500-gal tank with a nice 4" (or deeper) DSB should be capable of absorbing the predation of a 4" sand-sifting seastar without detrimental consequences.

[wozza]

well the star is now back at the shop and i got a firefish for the refunded cash, i must say the firefish is more active than the star ever was hahahaha