"Tube-snouted Ghost Knifefish" (Sternarchorhynchus goeldii), Loreto, Peru

Knifefishes are amazing animals for a variety of reasons – not the least of which is the fact that they can generate and detect weak electrical fields around their bodies. I say “weak” but there are exceptions – electric eels belong to this order (Gymnotiformes) and they use their strong electrical discharges for stunning prey and in defense. Most commonly, the electrical fields in knifefishes are used to navigate their surroundings, find food, communicate between individuals, and even identify specific individuals (same species). The ability to do all of these things allows these fishes to live in turbid and dark waters, not relying much on vision. Also, the highly variable nature of the snouts of these fishes (variable between species) allow them to become specialized feeders - often eating species specific diets in highly refined feeding niches. There are over 200 described knifefishes and undoubtedly more awaiting discovery. Fish are a huge part of the biodiversity of these rainforests and are an integral component to healthy forests - including just a few of the many species of knifefishes, one of which is depicted here "Goeldi's Tube-snouted Ghost Knifefish" (Sternarchorhynchus goeldii). This individual was photographed in Amazonian Peru.