NOT Getting any Coral Growth in my pico. WHY?

[liveclown]

I am not getting any coral growth in my 2.5 pico. Corals seem fine(as in, not diminishing) But no growth. What parameters could be off to cause this. Would a fish in there now, be to much bioload. Should I take him out. Would to many nitrates affect corals. I have almost 7 1/2 wpg. Caral: zoos,purple mush., gsp. xenia.candycane