Feeding a greater siren?

As part of a population study, I'm keeping a wild-caught greater siren in the lab to test a marking technique (fluorescent elastomer) and make sure the marks stay visible. However, I'm having some trouble getting it to eat and wanted to see if anyone has any suggestions.

The siren is about 12" long, in a 65 gal. tub with ~55 gallons of water in it. There are plenty of terra cotta and slate cover objects, plus masses of aquatic plants like southern naiad and duckweed. The substrate is small gravel; would sand be better? How difficult is it to clean a tank with a sand base?

Also in the tank: a small group of mosquitofish, many freshwater shrimp, 3 small crayfish, snails, small diving beetles and mayfly larvae, and 2 brown hoplos that are 4-5" long (Hoplosternum littorale, an exotic armored catfish). I'm trying to give the hoplos away because I think they might be competing with the siren for pieces of worms, but nothing in the tank seems to be bothering the siren too much or picking at its gills. The siren was collected from a roadside ditch in Myakka River State Park here in Florida (with research permits) and the fish, inverts and plants were also collected from nearby habitats.

I had hoped the siren would eat the fish, shrimp, crayfish or snails, but from reading previous posts, I guess that's not very likely. I've tried feeding it freshly killed freshwater shrimp, earthworms (both whole and pieces), and some shrimp paste that other people were feeding to freshwater fish in the lab, but I haven't observed it eating yet. In fact, the siren actively flees when it bumps into a moving piece of an earthworm. Should I try trout chow or bloodworms next, or maybe feeding it in a smaller, separate tank?

Thanks for any suggestions on changing the enclosure or the food!
-Sarah


(The first picture below is the ditch I collected it from, then pictures of the tank setup, and then a picture of the siren under some terra cotta pieces -- sorry about the poor image quality on that one!)

I feed all of mine on trout chow. The sirens under 6 inches get fingerling pellets, and the big guys get the bigger, floating ones (not sure what size), but they seem to love inhaling those little pellets, and mine have grown quite a bit.

I have a leser siren and it eats fish crickets and worms by forceps. but mine is special. it swims upside down and floats in a ball when resting. besides that its healthy. (i think) but you could try really long forceps.

I have fed mine freeze dried tubifex worms, angleworms, nightcrawlers, frozen brine shrimp, and trout chow. They have eaten all those things eagerly, although it takes them longer to find the tubifex worm chunks if they haven't had them for a while because they float. When I put in food they start looking for it when the chemical cue reaches them. There is a few minutes pause sometimes if they are inactive. It seems possible that it could be hard to see in your setup whether the food has been taken. If you put in a worm or a nightcrawler, do you know for sure what happens to it? My sirens are very accustomed to their setup, and not at all skittish unless I do something alarming like drop a book on the floor. Yours, being newly captured, might be quite a bit more sensitive to cues like light, stange vibrations, or the shadow of a potential predator above. I have seen one of mine startle when encountering a worm. This was immediately after a substantial water change, so I think it was alarmed by the state of the world in general and not in an eating mood. It's chemical senses may also have been thrown off by the water change. It ate one later. I also think that worms might smell more like food when they are first put in than they do later. I can't say for sure because mine get snapped up pretty quickly, but when I was fishing as a kid my Dad would tell me to change my worm if I hadn't had a bite for a while. Might your siren may only eat at night? I like your setup. Does your siren actively explore it in the daytime, or only at night? One thing to try might be the freeze dried tubifex worm chunks because if they are uneaten, they will probably still be floating in the morning. You might be able to se if trout chow was still there in the morning, although with your substrate I'm not sure. Of course you need to avoid loading your system with uneaten food. Good luck, and let us know how things work out.

-steve Morse

I recently posted on my blog http://www.bombina.co.uk/Aquarium_Podcasts/Home/Entries/2009/1/18_Fussy_Eaters.html
all about feeding problem aquatic animals, mainly fish but it works just as well with Axolotols and Aquatic Newts. Feed them with cooked prawns drop one in the tank and they will smell it and begin to frantically search for it and eat it. With your Sirens i would do this after the lights have been out for an hour or so to ensure they are active and feeling secure. Good luck let us know how you get on

Little bit off this threads topic...Just watched one of my sirens rip bits of algae off of the tanks back wall and eat it. I've been told that sirens don't eat vegitation except by 'accident' via feeding on other things. This is proof to me that this isn't true. As for an answer to this thread I would say to try (although small) blood worms. Mine love these.

Oh, live blackworms are also a favorite.

I have a couple large Greater Sirens. I think it was a stress related problem because they're WC. When I first got them they didn't eat for 1-2 months. After that they started taking chopped earthworms and soft salmon pellets. If I was you I would try throwing in a little food every now and then and see if your siren will take the food. Place a bowl or something in the enclosure and leave smaller amounts of food in it and just wait. Try not to use large amounts of food because uneaten food will spoil the water quality.

Tried feeding my Siren Smelts last night. It's a type of frozen fish available here as food for animals. Unfortunately they didn't take to them. I watched the Siren try to eat it a couple of times but it just spit it back out. I checked again in the morning to see if it had been eaten, but still no interest. So, Smelts are off the list for feeding time for us.