Maybe Synodontus would be better.
It depends on your setup and the tank's footprint. If you don't have many other bottom dwellers and there's enough open swimming space (not too much bogwood or rocks in the way) then it will be fine. If it's stressed, it's either less active and hides - or will start to display odd behaviour - swimming up and down just in one corner, etc.How do you tell if they're stressed? I have a pictus in a 30gal tank and he seems happy (had him just over 1 year now)