I’ve had these decades ago, their mouth is hard like a bird beak, they could snap a guppy in half with one bite… good thing my smallest tetra is like 3 times the size of a guppy in this tank…
so, this is a fish I wanted for quite a while… I think my tank is perfect for it, dark water, highly shaded by terrestrial plants, and emergent anubias… there is heavy flow on one end, but surface plants go across the middle of the tank, making the surface on the other side of those plants like glass… it’s a 24 inch deep tank, so none of the other fish are normally in it’s area, and even the smallest of the tetras are more than a mouth full… the tank is open topped, but is a top aquarium in the rack, built into a wall, so the sides go up 18 inches to the ceiling, and are filled with terrestrial plants… the high flow end on the other side of the surface plants is open for servicing the tank, but it’s not the type of area the butterfly will go into, and would require jumping over a full width hang on the side filter… I’m happy it’s eating processed foods… I could get into wingless fruit flys as a treat for several of my fish…