In saltwater lighting is basically broken up into reef and fish only lighting...a standard fluorescent fixture is fine for just fish and some non photosynthetic inverts...reef lighting is upgraded light fixtures such as power compacts, metal halide, VHO, T5s or other more intense light...this lighting provides the intensity and spectrum necessary for photosynthetic organsims...eg corals. If you sticking with some fish and a little rock a fluorescent is fine, it may nto give you the true colors of the fish but you could always upgrade in the future.