It’s fascinating that a Characin can breed like labyrinth fish and provide bi parrental care of youngs. There are many convergent evolution of body shape across fish species, but convergent reproductive behavior of bubble nesting is rare, specially in Characin which typically scatter eggs, abandon and eat youngs. The babies are quite large, comparable to mouth brooding cichlid than labrinth bubble nesters. How large are the parents? Pike characin can reach 28 inch and your tank, 48x24x20 inch, hardly enough room for adult fish if they reach max size.