If they are Salivator, a single pair rarely works, in a 20g even heavily planted the male will destroy the female, give it a week or 2 and she will be dead. The Salivator and the Borneensis make Irrubescos look tame. A male Salivator is an impressive sight but on its own seems a little sad. Out of all of those the Abei is probably your best bet, it will get to 3-4" and can be quite ineractive. Tanks not big enough for a Palembangensis. Cutcutia if they are them are nice looking little puffers.
