Tridacnid clams may be known as giant clams, but that doesn’t mean they are completely out of the question for owners of nano and small sizes aquariums who have a certain penchant for the gorgeous bivalves. The crocea (T. crocea) and maxima (T. maxima) clams stay the smallest out of all of the clam species available to the aquarium trade, and most are offered in tiny sizes that fit in perfectly into any small tank. Of course, with any clam in a small tank, they will need plenty of space to extend their mantles to soak up the light rays. So, offer them plenty of room by using an open layout with minimal rock. If placing the clams in the sand, it helps to position a flat piece of rock under the clam so that they can attach to the hard substrate.
For the record, we do not recommend clams in the smaller nano aquariums like the 12-gallon tanks or any of the pico aquariums. The larger models, those 20-gallons or larger, are far more suitable.