A few general recommendations I would make:
As many circuits as possible into the fishroom. Ideally, each circuit would also feed some sort of light or other frequently-used device in the main living area of the house, just to alert you in case the circuit breaker trips. Otherwise, you wouldn't know until your next trip down into the fishroom. Could be as simple as a simple red LED light over your kitchen counter or elsewhere upstairs to indicate the fishroom circuit is live.
Full GFCI (Ground Fault Circuit Interruptor) protection on everything in the fishroom. These will trip if you splash water on a receptacle or drop some device into a tank. They react almost instantaneously, fast enough to prevent a dangerous shock to you. They can either be simple GFCI-protected powerbars (better than nothing), GFCI receptacles (much better option that can be wired in such a way as to provide GFCI protection on other devices like lights), or (best of all) proper GFCI breakers in the panel.
I like to make sure that each tank is filtered/aerated by devices fed from two different circuits. This way, if one circuit trips for whatever reason, the other remains live and every tank still has some water movement and aeration. I have a central air pump that feeds a sponge filter or at least an airstone in every tank, and it doesn't share a circuit with any other pumps or filters.
I would also place all receptacles on the ceiling or high up on the walls rather than the traditional location near the floor. Far fewer splashes or drips introducing water into a plug that way. Seeing receptacles or powerbars mounted inside stands makes my skin crawl.
