Hi KevinPuppy
Why not?
If your tank is very mature so that sandbed and rock is deeply evolved, all the better. Otherwise rely on frequent water changes until then.
The surface skim will be your challenge with this set up. A bubbler would help, such as the result of a sponge filter, but it sprays droplets everywhere that dry into corrosive salt crystals and frosts the glass between cleanings. A lot of turnover at the surface, like a gyre wavemaker or return pump nozzle directed parallel with the surface is an idea, too. Ocassional lifting of skum with paper towel may be necessary. I have had many small tanks. New pico has a sponge filter. Waterbox with canister filter has no overflow. The challenge is to keep things oxygenated everywhere, no dead corners.
Clowns get pretty big and eat a lot. It seems smaller fish would suit your filtration idea better. I think you would get a lot of oily skum with two adult clowns. FWIW, I read a pair needs a square foot of territory, at least. Might be uncomfortablely tight for a third fish when the fish mature.
Maybe a pink streaked wrasse, firefish, shrimp goby and pistol shrimp pair, striped fang blenny, royal gramma, something along those lines. 2” or less
