Fish that have adaptations (spines, sticks, venom) that protect them from predators. These include: electric fish - fish (rays) armed with special organs that produce electric charges for obtaining food and protection from enemies; highly developed fish with a cartilaginous skeleton and skin with placoid scales made of dentine. In the marine and freshwater faunas of low latitudes, the number of fish species "armed" with spines and thorns is much greater, and the "armament" of fishes is usually more developed than in the faunas of high latitudes. Spines and thorns, with or without venom glands, are usually developed in slow swimming demersal and benthic fishes. Spines and thorns are much less common in pelagic fishes.