are you kidding me ornate bichirs get at least 28" even curviers bichirs get 12" which is too big for a 20 gallonYou could keep a bichir. Bichirs are my favorite fish! I love how they stand on their fins! Any bichir is good but try going for a Ornate! Those are pretty! Those also could go for maybe $25 to $40. Not that expensive![]()