So, its been frustrating trying to get decent photos of the fish, mostly due to focus issues, with lighting being the other challenge. I just use the built in flash, so reflection would be a problem. Now, to deal with any glass reflection from the aquarium, I hold the lens against the glass. And for a couple of reasons, I found that holding the camera upside down produces better results. The images are easily flipped in Aperture.
And that leaves focus. Because there is little distance involved, the only lens I can really use is my 10-22, but on auto focus it wants to focus on the backdrop of the aquarium. So I set the focus on manual, find a distance and try to judge when a fish is the right distance from the camera. Needless to say it is a less than perfect set up. Here are a couple of my better results.
These are the bad boys of the tank. The dominant male is the fish in the centre. He matured first and rules the tank. The blurred pale male is the main problem in the tank, I believe. It is by far the most aggressive of the tank, both towards the females and the less dominant males. I think this is the fish responsible for the tank mortalities.
My female with the interesting behaviour is the large in focus female in this photo.
This young, but large male, has a very interesting, subtle, almost iridescent colouring, that unfortunately this photo fails to do justice to. It is also very meek, and has been run roughshod over by the paler male.

Comments
2 responses
Pretty clear shots.
Iridescence is always a problem. I have the same issue with my large polychaete; in real life, it is absolutely stunning. The same shifting blues, silvers, pinks, all coming out in the photo as fuzzy splotches of colour. I think the difficulty lies in that what we see is the skin as it is, blended with as it is in memory, an instant ago. The camera has no such depth.
A close-up filter set for the end of your lens might help.
http://www.google.com/products?hl=en&client=safari&rls=en&q=macro+filter+set+77mm&um=1&ie=UTF-8&ei=G8ciS4CkPJOvlAe3l-T4CQ&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CBgQrQQwAA