Ashley,
There is a
lot of diversity among the sponges, and like any other group (such as cnidarians, echinoderms or fishes) you can't make generalizations based on one that will ever apply to all of them Asking about an "orange sponge" is sorta like asking about an "orange fish," you're not going to get much useful information... In fact, it's even worse with sponges -- at least all fish eat something and it's just a matter of finding out what that is and providing it. The same cannot be said of sponges -- some sponges feed exclusively, many get most of their energy from the uptake of dissolved organics, and others are obligately photosynthetic and are primary producers more similar to an alga than another animal in tank care requirements! Although sponges all seem simple and similar to us, that amount of diversity makes it very difficult to offer any generalizations about these animals that can be broadly applied...
There are some good articles on sponges already on the web, so I'll refer you to them first. In the archives of Aquarium.Net, you'll find
an article I wrote, and one written
by Ron Shimek, as well, that I think give some of the most detailed information on sponges. Ron also has a couple of nice articles in the archives of Aquarium Frontiers on sponges --
Part 1, and
Part 2. In addition to these more detailed articles, Jim Wolf has a series on sponges posted on the
MASLA site, that gives a nice basic introduction to these animals, and Bob Fenner has some nice pictures of many of the most common varieties found in the hobby along with a basic introduction to the animals on his
WetWebMedia site. Beyond that, if you're looking for some specific information about which sponges do well, and which do not in captivity, Julian Sprung's new book
Invertebrates: A Quick Reference Guide has pictures and a rating for each of the common sponges sold in the hobby along with a brief mention of any special considerations necessary to keep these animals.
That should be plenty of introductory reading for you to get started on how sponges work, and what it takes to keep sponges alive in cpativity...
Rob
