All of the different catfish species are available in a purchase that contains no less than 37 different families. The 37th catfish family was really added to the order very recently - June 2005. The majority of the different catfish species are freshwater dwellers. Catfish have adapted to a wide range of different ecological niches you can find small catfish species as well as huge ones such as the Wells Catfish that may grow up to five meters (16 feet) long and the Giant Mekong Catfish that can weigh almost 300kg (661lbs). Both of these big catfish species are naturally not very suitable as aquarium fish, but there is a vast array of other species that you can keep even in a moderately sized aquarium. Catfish are extremely popular in aquariums and many species can be kept even by inexperienced aquarium keepers. A couple of typically the most popular Catfish among novice aquarium keepers are the Sucker mouth Catfish and also the Bristle nose Catfish .
One of the most distinguishing anatomical characteristics from the catfishes is the prominent barbells found near the mouth. A barbell is really a long, tactile organ that's very helpful for fishes that live in murky waters where the visibility is limited. The catfish will use its barbells when hunting and maneuvering in dark environments, as being a cat will uses its whiskers. The barbells of the catfish do however have taste buds and also the catfish can therefore "taste" its environment. You can find barbells on a number of other fishes in addition to the catfishes, including goat fish, a few carps and some sharks.
In addition to barbells, the various catfish species share another notable anatomical feature - they're scale less. Catfish all families but one are also designed with a hollow leading ray that may excrete a powerful protein to discourage or injure potential threats. Some species may even harm humans and must be handled very carefully. There is one catfish family where the species don't have any hollow leading ray. These species can not produce any stinging protein, and can instead protect themselves by sending out a very powerful electric shock. Due to this capability, the species are called Electric catfishes.
Another illustration of a fascinating catfish species is the "Vampire fish of Brazil". This catfish is popularly referred to as the "Vampire Fish of Brazil" because it will attach itself to the gills of other fishes and drink their blood. This fish is not extremely popular in Southern America because it sometimes attempts to attach itself to swimming humans, when attracted to blood or urine excretion. The body of this catfish is nearly transparent, which makes the fish quite hard to spot in the water. The fish can also be quite small, only 2.5-6 centimeters (1.0-2.4 inches) long.
photo by http://www.asiatropicalfish.com