A nice enough diversion, but there's not enough challenge to hold anyone's interest for a long stretch of time. If it had been more of a simulation, like Zoo Tycoon in a tank, then there would be much more to do, but as it is, this game is more of a time-killer than anything else.
Ultimately My Sim Aquarium is a good diversion for youngsters that want to casually try their hand at taking care of fish. For adults the game may not be so fascinating.