Terry,
My crinoid knowledge comes, primarily, from Aquabacs, and what I've been able to find on the Internet, which isn't much. Mike is the expert. I've only owned mine for a month, though I've studied crinoids rather thoroughly, since buying mine. Here are a few things I know:
--If they're moving around, something isn't right and they're burning up energy, so you have to make sure they are well fed, in addition to finding the problem.
--If they're losing arms, it's also a sign of trouble. Mine lost one arm after I initially put it in the tank. No arms have been lost since. I assume it's growing a replacement, but I couldn't find which arm that is in that mass of feathers if I tried.
--There are two basic kinds--One perches on rocks or other surfaces in the open and spreads its arms in a fan array to capture food. The other type tends to crawl into rock creases or some other hiding place and then put its arms out in random directions to collect food.
--Mine will curl up much of the day, opening a few arms if food is in the water. In the morning and evening, and I assume night, the arms will be spread quite a bit.
--My nitrates are high right now and my crinoid is not happy. It was wandering all over for the past four days. As of yesterday, it settled in one spot and hasn't moved. That coincides with my bio-pellets starting to have an effect on the nitrates. I hope it's getting happier.
--They feed with their mouth/front side of the arms downstream. They're more efficient at grabbing food that passes through the "backside" of their arms. The tube feet along the pinnules grab the food and put it in the ambulacral groove that runs along the front side of the arm. Food passes down this groove to the mouth.
--They can capture food that strikes their front, but are not as efficient at capturing it and getting it to their oral opening.
That's a quick mind dump. Hope it helps,
Gary
