My gorrilus umbee pair or dovii pair may get upgrade.. Both deserve it. The question is which pair is more active in old age? Both approximately 16" and few years old so potentially have lot of life left in them. One day I like this pair better and next that pair so it's not a question of people's favorite because tomorrow my favorite will switch then next week switch back. Dovii better parents and I enjoy watching them raise fry but the umbees change color like a chameleon. So I know both will be amazing big tank with 5'x3'+/- footprint. Umbee younger and grow faster but dovii may top out larger ultimately, regardless I don't like moving big fish and prefer them taking up permanent residence. So the deciding factor is who swims more in old age. Dovii probably more ambush predictor while umbee open water hunt more by nature... but in less than 15sq' surface area they will not be acting true to their instinctual habits. So dovii pair or umbee pair move around more when they hit 20" in small glass box
