Yes you can keep anything under metal halide. You can keep pretty much anything under t5, depending on the watts, and how close the item is to the light. I have an ann and sps in my tank with t5 and they are fine. They prob wont grow as much as under MH, but I like the option of having different collor bulbs and being able to combine any bulb i want. I dont think i would put a clam under my t5 but i have seen it done several times. From veteran reefers