That's a tall order. Your camera doesn't shoot in RAW, so getting colors right under high color temp lighting will be challenging and custom white balance will be your friend.
Fish are tough to shoot in our comparatively dim tanks, because they tend to move and thus require a very brief shutterspeed, like no slower than than 1/100, and that may not be fast enough. With a dim tank and a fast shutterspeed, you'll probably need a large lens opening (low number fstop) and a higher ISO, like 800-1200.
Good luck.