Which ones?

[paranda]

Hello,
Which clams would do well in a 55G (48" X 13" X 20") with 2 10K 175W MH lamps? Are Actinics needed for clams?
Thanks,
Peter

[MiNdErAsR]

If you can find a T. maxima or T. crocea which is already attached to a rock, then you could place it high in your system, and it should be ok. Otherwise a T. derasa in your sandbed will be fine.

IMO

[OrionN]

IMO, your tank is too small for Gigas or Derasa (my Derasa goes from 3 inches to 6 inches in 6 months). You don’t have enough light of Crocea or Maxima to keep their beautiful color. You can keep them alive and doing well high up and close to the light. This makes viewing difficult.
The only choice is a nice Squamosa. These clams need less light than Maxima or Crocea. Thy are very beautiful and grow slower than Derasa