Marine invertebrates come in a huge variety of shapes, sizes, and functions. Most of them fall into two categories for aquarium use, being either a functional part of the cleanup crew or just as an accent piece. Either way, it’s crucially important to know just what your invertebrate needs to thrive. For example, clams are photosynthetic and need plenty of sunlight, among other things. Sponges, on the other hand, are excellent filter feeders and don’t require very much light, but you may need to feed the aquarium rather heavily. Unfortunately, far to many people purchase invertebrates that have no business being in captivity, as their diets are far too specialize to recreate in captivity.