Harlequin Shark

About

The harlequin shark (Labeo cyclorhynchus) is a mid-sized cyprinid from the Congo River basin and the Ogowe River in Gabon and Central African Republic, where it lives a largely solitary life among the lower reaches. Juveniles are genuinely attractive fish, wearing a variable, high-contrast pattern across the body. But prospective keepers should know that this fades considerably with age, adults tending toward a much darker, more uniform appearance. That's not the only surprise waiting for the unprepared: this is one of the more aggressive freshwater fish you'll encounter at an intermediate care level, and its territorial instincts intensify noticeably as it matures. Keeping two together is a project best avoided except in very large, heavily decorated setups, and even then expect friction. Bottom-dwelling tankmates like cichlids and catfish tend to draw its ire, so the best companions are robust, active mid-to-upper water swimmers, particularly African characins. It has not been bred in captivity as far as anyone knows. The species was described under two different names within just a couple of years in the early 1900s, and the synonym Labeo variegatus still turns up occasionally in trade lists and older references. Best kept as a single specimen by a fishkeeper who knows what they're getting into.