To start off, I suggest to no longer use Caps Lock, since it is hard to read and considered shouting
To answer your question: Your cat should have no access to an open tank (fish are cat food), and your dog should not have access to anything chewable (power cords) and - for a small tank and big dog - the stand should be secured so that it doesn't top over if the dog bumps into it.
my cat has found a new meaning to life
sit on the back of the couch, and watch the fish, maybe bat at the tank when some of the larger specimens swim by... she will sit or lay and watch them for hours day after day...