there would be a number of useful things to actually know here....

1) what are you using dynamics for? and as part of this, why doesn't this work for your animation?

2) Is that the final fish tank, or are you going to make a different one later? (this spools into a number of refraction questions....)

3) If you haven't thought of this already, it would be best to have a seperate shader for the tank itself, and something else for 'underwater', cause the water shouldn't come all the way to the top of the tank.... Currently it looks like you're trying to make the tank an underwater color, when it should be much lighter...