Clean glass, of course
Because most shrimp are so small a macro lense or a camera with a good macro function is a must.
If your digi cam's macro function is not so great you can still get decent pictures. Set your camera at it's highest resolution(eg: 5MP) and get as close to the shrimp as you can while it's still in focus. This way you can still crop the higher resolution picture to focus just on the shrimp.
A tripod or something to stabilize the camera is an ABSOLUTE MUST HAVE! Because you're dealing with such a small subject, the slighest movement of the camera while the shutter is open will show up as a big motion blur.
Macro shots have a tendency to only focus on a specific point. For example, your shrimp's head might be in focus but the tail or legs may seem blurred. Most camera automatically set the aperture(some call it f-stop) as low as possible to let in as much light as possible when taking macro shots. A low aperture setting will produce an in focus foreground with a blury background. If you want as much of the fore/background as possible to be in focus, set the aperture as high as it will go. Of course you will have to either adjust the shutter speed accordingly(can cause real problems with motion blur) or use a flash.
The flash... I really hate to use it but it's a must with fast moving creatures. Every one knows that flash + glass = glare. To combat this, bounce the flash off something. The best thing to do in any aquarium photography situation is hook up an external flash(most cams have a hotshoe for one). Take the hood off the aquarium and point the flash at the ceiling. The light will bounce off the ceiling and iluminate your picture. If you have tall ceilings, try using some white board placed above the tank.
Things not to do: Avoid long exposure times(slow shutter speeds). This gives the animals a chance to move and create motion blurs. If possible use a low ISO. Higher ISOs are great for low light situations but produce grainy pictures.
Hope that helps and wasn't too confusing. I've been doing photography for about 7 or 8 years so my appoligies if that sounded like a bunch of technical jibberish.
Photographing shrimp suggestions
In another thread the subject of photographing shrimp was brought up, and I thought that a thread on that topic might be a good idea. Since shrimp are so very small, they present a challenge. 
I am using a Nikon 5400, a SB28 flash with bounce card and close up lens.
Linear Mode
