I have a 6" in a 46 bow with a power filter, temp 78, coral sand, bushynose pleco that swats the gulper with his tail (funny to see) & one giant Danio (others were eaten) He did eat a 6" pim cat. I feed algae wafer, hbh soft krill, fish etc..
20 gallon long I say would be fine for one for awhile. They do not get to big so maybe 30 or 40 breeder eventually would be ideal.
I'm trying to ship in a box of small/baby ones if & when available?
me dave