1) Before you attempt taking pictures clean the glass inside and out
2.)take the pictures at night with all light sources off except the tank
3.)get as much light as you can into the tank add lighting if you can
4.)use the fastest speed your camera has
5.)NO FLASHES it washes out the fishes color.If you can't control the flash put a piece of masking tape over it to diffuse the bright flash.
6.)Press the shutter button half-way down to focus, than all the way down to take the picture. thank you vanimate for this one.
7.)Do not use digital zoom, only optical zoom for really clear pictures
8.)shoot from a tripod
9.)A remote shutter release(if possible for your camera)is best because sometimes presing the shutter can shake the camera
10.)give the camera time to auto-focus... do not rush pictures
11.)let the fish come into your view of the camera,don't chase it down
12.) Plenty of light: The more the better, no matter those are tank lights or top-down flash light. Lighting is the key toward good aquarium photography (actually, apply to all photography cases).
13.) Faster shutter speed: 1/100s and faster is safer, and 1/200s is nearly OK for turning around bichirs.
14.) Smaller aperture size (the larger number): 11 or above (the smaller aperture the larger depth of field).
15.) Top-down external flash light on tank top is good (studio flash light is even better), built-in flash light is not good.
16.) Be patient, and spend more time (you'll get reward).
I mostly use 1/200s~1/250s, F16~22 for aquarium photography (I do setup plenty of lights for the tank)
