The problem that he will probably run into pretty quickly is that the water at the bottom of the tank will not have enough dissolved oxygen for the fish you have to offer to live. If he could extend a bubbler tub all the way to the bottom so that he can keep the water churning maybe they might have a chance. I would also be afraid that he wouldn't be able to do a proper cleaning of the substrate regularly. Although it is a neat idea, that I myself played with for awhile, it’s over all too difficult to keep up in the long run. If he really insists on using it you probably should warn him that the fish are not going to swim at the bottom and if he is ok with that maybe a labyrinth fish would be acceptable, So basically we come back to the basic beta scenario. Or maybe a dwarf gouramis they only get to around 2.5 inches and will be able to breath off of the surface.
Another funny tank: i am watching my roommates friends betta over their christmas break, so apparently it ususaly lives in a 4 foot tall Champaign glass.
Another funny tank: i am watching my roommates friends betta over their christmas break, so apparently it ususaly lives in a 4 foot tall Champaign glass.