I’d probably suggest a T. crocea, as well, though you could also keep a T. maxima healthy, depending on your lighting. You’ll want a spot where the clam is getting plenty of light, but not getting blasted with flow.
One more thing to consider, since you’re new to clams…
Don’t get a tiny one. Get one that’s at least 3″. The tiny ones are so cute and beautiful, but have a lower survival rate.
Okay, one more thing to consider…
Remember, the clams will look completely different, when viewed from the side, rather than viewed from the top. If you’d like to see examples of this, come on over and look at our clams, through the glass and then through a look down box. Clams are most beautiful, when viewed from directly above. Unfortunately, with most tanks, this is not how we’ll normally view them.