Crocodile Stickleback

About

Armoured Stickleback (Indostomus crocodilus) is a genuinely unusual little fish from the blackwater streams of Narathiwat Province in southern Thailand, where it lurks near the bottom among dense vegetation in soft, acidic water. Adults barely reach an inch in length, and their bony, ridge-plated bodies place them in a family with only three known species worldwide. Close relatives of sticklebacks and, more distantly, pipefishes and seahorses. Males can be identified by dark brown to black bars in the dorsal and anal fins, a white throat, and weakly serrated ridges along the head bones, which sets them apart from their two congeners. Despite a listed temperament of aggressive, most of that attitude is directed at rival males over territory, and actual physical damage between individuals is rare. The bigger concern is keeping them away from anything large enough to eat them. They are genuinely poor competitors. Companions like small Boraras or Dario species tend to work well. Though not a true schooling fish, a group of four to six individuals brings out far more interesting behavior than a lone specimen will show. Breeding happens in caves or tubes, with the male guarding eggs deposited on the ceiling of the spawning site and tending the brood solo until fry are free-swimming. Rearing those fry is the real challenge, as they emerge tiny enough to require microscopic foods.