If i try and take a pic of a fish, its blurry. I hate using flash because it makes the tank look fake. I like the way the aquarium lighting looks, so how do i do that?
Fish are some of the most difficult things to photograph, especially if you're trying to catch a fast-moving wrasse or such. I'm often forced to use a higher ISO (such as 800) combined with a small aperture (<4.0) to get a decent picture of a moving fish. Depending on your camera, you may not be able to get a clear picture of your fish without a LOT of effort and trial and error.
One technique that might help is to prefocus: usually when you depress the shutter halfway, the camera will lock its focus. What you can do is guess where the fish will be, and focus on a rock or something nearby where you want the shot. Then comes a bit of patience as you wait for the fish to wander into an area where you've focused. This takes a bit of practice, but can yield surprising results. This technique combined with a higher ISO setting (and therefore higher shutter speed) could be what you need to get a decent shot. And, above all, practice practice practice. Dont' give up!