Lower light clams(deep water) such as T.gigas,derasa,squamosa are hardy.
T. maximas are much more light demanding. Wild caught clams such as ponape clams and vietnam teardrops require direct MH light. Farmed (ORA/Marshall Island) clams(both ultras and 1st grades) seem to be more tolerant of different lighting.
All these clams do better with feeding IMO...regardless of size.
Adam