On the subject of flash reflection it's important to get the flash bulb away from the camera when it is triggered. This is the beauty of the sync lead and/or a slave flash. I often use a flash that's several feet away from the lens. This provides more even light for a tank and no reflection, except perhaps off aquarium objects. The light also looks more natural than the "ring" flashes you might see some people use.
If you have a built in flash you need to work around the reflection problem. Here are some tips:
- Sounds obvious but don't shoot right at the glass. Shoot at a slight angle to the glass.
- Get the lens as close to the glass as possible (usually only possible if you have a good macro focusing distance and a cooperative animal).
- Generally more of a problem for built-in flash, it's a good idea to remove any glossy or reflective materials from the immediate vicinity of tanks. They can really destroy a photo - examples: polystyrene boards beneath tanks, plastic table tops on which tanks sit, other tanks. If you can't move it, cover it with something neutral in colour and non-reflective. It's good to figure this out asap because you never know when you might have a wonderful photo opportunity but have it ruined by a nearby object.
As for lighting, I assume you mean the bulb in the tank and using relying on its light instead of a powerful flash system?
If you are using a digital camera you can easily counter this by getting a piece of white card or neutral grey card, shining the tank light directly on it and using the measure pre-set white balance option on your camera.
If you're using film, you can get different temperature films for different situations, but the key really is to rely on a flash system for lighting. Things get a heck of a lot more consistent. And there's always the photo editor aprés shoot.
I urge you to experiment taking photos in every way you can. Coupled with (hopefully) good advice, it's the best way to learn.
That's what springs to my mind right now. Anyone else care to chip in?