WHAT happened to my starfish?

[Tnops]

I haven’t seen my sand sifting star for a month and thought it had died (I have had it for over a year by now). Today I found this, it is apparently still alive but has all of its arms ripped off.

How did this happen? The only culprits I can think of are blue throat trigger, copperband, and radiant wrasse but I haven’t seen any of them attack it

Maybe it got caught in a pump? Does anyone have any experiences? I am fighting cyanos if that helps

 

[VintageReefer]

It is starving and wasting away. This is common for sand sifting starfish. They eat all the food from the sand then deteriorate and waste away.

 

[ISpeakForTheSeas]

Yeah, from what I've read, ~8-13 month survival is pretty typical for starfish in our tanks; as mentioned above, it's believed that they starve to death around that time:

In most cases, the first symptom people notice is the star dropping legs (typically caused by starvation). Sometimes you'll find issues like the star starting to visibly deteriorate (looking like they're disintegrating in places or like they've been attacked by something), but that's typically from disease (as I understand it).

Have you been feeding it anything, or just letting forage in the sandbed?

Some feeding advice for these guys (as mentioned below, I'm still waiting for someone to tell me if they took the advice and if they found it helpful or not):

You can target feed them, but no one has gotten back to me yet on if it helps:

These starfish don’t eat algae in any meaningful quantities. They’re probably carnivorous, but may be detritivorous (see the quotes below). Personally, I’d try putting the star in an acclimation box with a dish of sand for it, and I’d try offering it a bunch of mollusks for it to eat (clams, mussels, oysters, and small but meat-eating snails like Nassarius snails would be my suggestions at this point), and see if it shows interest in eating any of them. If it does, then I’d try offering it more of that item in various sizes and see if it has a preferred food size.

I'd try something like clam, oyster, etc. and/or snail meat (you can find various frozen/live marine snails to try online, including conch meat, periwinkle snails, babylonian snails, etc.)

The quote below is specifically geared toward Astropecten spp. (predatory) sand sifting stars, but there is another genus of sand sifting stars called Archaster that is thought (importantly the diet was inferred, not studied in the research that this diet was pulled from) to be detritivorous (specifically, they are thought to be microphagous detritivores). I have heard but cannot confirm that Archaster spp. misidentified as Astropecten spp. may be more common in the hobby than actual Astropecten spp. are.

So, with this in mind:
- If your star is detritivorous (which may be a very big if), then you would likely want smaller foods than the suggested below (which is designed for predatory sand sifters). In this case, I'd suggest trying to mix something like TDO Chroma Boost into the sand for your stars to find.
- If your star is predatory (which may to our limited knowledge be possible at this point even if it is an Archaster sp.), then the below advice (and my advice above) is more likely to be useful.
- If your star is actually primarily a biofilm eater like Linckia spp. Protoreaster nodosus, etc. (which may also to our limited knowledge be possible for an Archaster sp.), then it's likely to die regardless of what you do or don't feed it at this point.

I’ve heard they climb the glass when they’re looking for food and can’t find any in the sand bed.

Generally, people recommend large tanks and waiting until your tank is established before trying these (or pretty much any) sea stars, and the star survives on detritus in the tank. Unfortunately, even in a lot of these tanks, after they finish clearing the detritus from the sand, they typically starve.

My current advice to avoid the star staving - which may or may not help, I genuinely don't know at this point (it could take someone months to years of testing it to find out for certain, as sea stars can last months without food):
Target feed the star things like clam on half shell, oyster, mussel, scallop, etc. (bivalves); snail, whelk, conch, etc. (sea snail gastropods); and a good quality omnivore food (like LRS Reef Frenzy or Fertility Frenzy). These are - according to the best sources of information I can find - the sorts of foods sand sifting stars consume in the wild, and the star should swallow these foods whole if they aren't too big - you might need to experiment a bit with the size of the pieces offered to get it sized just right, but generally I'd say err on the smaller side.

If you decide to give it a shot, let me know how it goes, and keep me updated on the long term survival of the star!