Spotted Hatchetfish

About

The spotted hatchetfish (Gasteropelecus maculatus) is one of those fish that makes you do a double-take the first time you see it. That absurdly deep, laterally compressed body is not an illusion. It houses an oversized keel packed with flight muscles that let this fish break the surface and skip through the air to escape predators. In the wild it ranges across river systems in Colombia and Panama, including the Magdalena, Caribbean-slope, and Pacific drainages, where it spends its entire life in the surface film, watching for insects and small invertebrates to drift within range. The scattered dark spots along the flanks are what set this species apart from its plainer relatives, though the deep silvery body shape is immediately recognizable as a hatchetfish regardless. In the aquarium it behaves true to form. A dedicated surface dweller that rarely ventures lower in the water column. A tight-fitting lid is non-negotiable, because these fish will jump at the slightest disturbance. They settle in best when kept as a group of six or more, and they appreciate surface cover from floating plants. This species falls into the intermediate category, mainly because it can be sensitive to water quality and takes some care to feed well on appropriately sized live or frozen foods.