Atlantic Serpent Star with strange behavior  7/18/08
Hello -
<Hello!>
I have a green Atlantic serpent star (his body is about 1.5" in diameter - his total length is far more than 12" when extended) in a 125 gallon tank with a lot of live rock, but not many other fish.
<By 'fish' you must mean 'snack food'...>
Yes, he's become quite the fish hunter, and his most recent kill was the Hawkfish he'd lived with for over 4 years (only a black long-spined urchin, a striped damsel and the blue tang are left of the 6 I put him in there with)...
<The urchin will survive...the others best beware>
Right after he'd eaten the Hawkfish I noticed some strange behavior. At first, he sat curled up in his cave for a few days, not even coming out for food (the Hawkfish was a much bigger meal then he was used to, however). Then, he moped in his cave upside down, with his mouth facing up and his back on the ground. Then, he moved to the front of the tank, where there's a lot of light, and where he usually never comes unless we feed him. He's still upside down in the front of the tank, and I thought he was splitting because there's a tear in his underside: his 5 arms end in pie-shaped pieces of body connected by disk-shaped pieces...on either side of the disks one can normally see his insides through slits or his central mouth. Now one of the slits is connected to the mouth, as the disk has torn completely away from the pie-shaped piece on one side. The slit hasn't gotten any bigger over 5 days, nor has the listless behavior changed (he just lies there, in the open, upside down & only responds to being poked or moved...not to food, nor the urchin, crabs, or snails walking over him). I also noticed a hard piece of white something shaped like a thin but flat shard of rock sticking out of the tear. I tried to remove it with tweezers, and it appears to be attached, yet I can't find evidence of a similar part anywhere else on his body. It looks like his more flexible spines are moving inside of him, but not much else is. His color hasn't changed, either.
What is this shard? if it's foreign, is it harming him? Is the body split normal? What about the behavior? Is this part of reproduction? I haven't been able to find hard answers on just how sea stars split (I had heard that they sawed themselves apart with their arms, but he's definitely not doing that), or pictures similar to what I'm seeing. I've tried to take pictures, but you can't really see the split or the shard well. Let me know if a picture is needed, & I'll try to get a better one. Any info would help, because if he is dying I'll get him out of that tank - thanks!
<Echinoderms have tremendous powers of regeneration. If this star appears to degenerate, consider quarantining it. Otherwise I would just let it be- no picking, tugging, feeding, etc.- until it recovers. This 'shard' is most likely a fragment of the cartilaginous tissue that makes up the internal frame for the water-vascular system.>
Laura Reed
<Benjamin>