Does the housing come with color-corrected lens? That was something mine did not have so I bought the wide angle and 3x closeup lens. Most of the pictures I take are with the wide angle lens that is color-corrected.
Without color-correction you tend to get a lot of green in the picture and not all of the other colors.
example:
With lens
Without lens
I also learned not to chase things. It never fails that if I try to chase a fish it will run away but if I just sorta float to it it will stick around.
If you have a digital camera take lots of pictures. I take hundreds of pictures but only have a 1/3 of them that actually come out right.
I also take blind pictures....If I see a hole that I cannot see in but my camera will fit I will stick the camera in a take a picture anyway. I have gotten some real good shots that way.
I went to St Thomas last year and had a blast doing shore dives at Coki Beach. Lots of fish and it's not to deep so you can dive forever on a tank. Plus the tanks are right on the beach so you don't carry them far.