4th tank ideas

So the lady approved a 4th tank for the house. I was wanting something smaller, perhaps in the neighborhood of 30 gallons or less, but I want something different. I don't like have two of the same tank, or multiple tanks with the same fish or coral. So what ideas can I do with a 30 gallon or smaller tank?


I already have an SPS/LPS 75 gallon


I have clowns, anemones, and some misc fish in a 65 gallon


and I have 2 designer clowns, with zoas and some hammer/torch/nps coral in a 21 gallon.





I feel like this tank is a Spousal Factor Trap because when you can't have something, you know a million different things you want. But the moment you're allowed to buy something you can't figure out anything that will look good. Oh sure you can buy another tank for the house, but it better be good.........