Crystal Rainbow Tetra

About

Found in Peru, this tiny Amazonian characid, Trochilocharax ornatus, turns up in the hobby under trade names like crystal rainbow tetra and orange-tailed glass tetra, and it remains genuinely uncommon despite being sought after by collectors. It is the sole member of its genus and stands apart from other tetras in some unusual ways: the body is almost entirely scaleless except in mature males, which develop a specialized scale near the caudal fin base that may be connected to pheromone production. Reproduction involves internal fertilization, a trait rare in characids, and in a well-established aquarium a few fry may appear without the keeper doing much at all. Behaviorally, it is a shoaling fish rather than a tightly schooling one, and rival males spar with each other regularly, which makes a group of eight to ten individuals both more confident and considerably more interesting to watch. Despite that intraspecific squabbling, it generally ignores other species, though its small size means it works best with similarly diminutive characids or small catfishes rather than a typical community setup. It also serves surprisingly well as a dither fish alongside Apistogramma and other dwarf cichlids, since it naturally occupies the middle and upper water column. Intermediate care experience is recommended.