Is the bulb a DE 150.........also depends on the size of the clam, but if you have a DE 150 I t hink you could get away with it....coloration buy the color you prefer , with the golds do not need as much light as the brighter colored clams.....just place the clam directly beneath the bulb on the bottom....on a small falt rock so it can atach and then you can move it around if necessary....like mentioned in the above post...