What a great idea! Kids are so curious, and this helps them learn about fish and pets, but might deter them from climbing on high furniture to get a good view of the a bigger fish tank higher off the ground in the living room, etc.
Already have a small lego table but son is outgrowing it. Would love to do this on a bigger size table for him. Would be good for a kid's playroom. If you did velcro to attach it, you could switch out the base plates maybe.