| All the different catfish species can be | | | | other fishes in addition to the catfishes, |
| found in the order Siluriformes; and order | | | | including goatfish, a few carps and some |
| that contains no less than 37 different | | | | sharks. |
| families. The 37th catfish family was | | | | |
| actually added to the order very recently | | | | In addition to barbells, the various catfish |
| – June 2005. Almost all the different | | | | species share another notable anatomical |
| catfish species are freshwater dwellers, but | | | | feature – they are scale less. Catfish |
| in the family Plotosidae and Ariidae you will | | | | from all families but one are also equipped |
| find catfish species that do not live in | | | | with a hollow leading ray that can excrete a |
| freshwater. Catfishes have adapted to a wide | | | | powerful protein to scare off or injure |
| range of different ecological niches you can | | | | potential threats. Some species can even harm |
| find small catfish species as well as huge | | | | humans and must be handled very carefully. |
| ones like the Wells Catfish that can grow up | | | | You should be especially cautious when |
| to 5 meters (16 feet) long and the Giant | | | | dealing with catfish specimens belonging to |
| Mekong Catfish that can weigh almost 300 kg | | | | the genus Heteropneustes (in the family |
| (661 lbs). These two big catfish species are | | | | Plotosidae), since a sting from one of these |
| naturally not very suitable as aquarium fish, | | | | species can require hospital treatment. There |
| but there is a vast array of other species | | | | is one catfish family where the species have |
| that you can keep even in a moderately sized | | | | no hollow leading ray, the family |
| aquarium. The Plecos are for instance very | | | | Malapteruridae. These species can not produce |
| popular in aquariums and many species can be | | | | any stinging protein, and will instead |
| kept even by inexperienced aquarists. Two of | | | | protect themselves by sending out a very |
| the most popular Plecos among novice | | | | powerful electric shock. Due to this |
| aquarists are the Suckermouth Catfish | | | | capability, the species found in the family |
| (Hypostomus plecostomus) and the Bristlenose | | | | Malapteruridae are called Electric catfishes. |
| Catfish (Ancistrus dolichopterus). | | | | |
| | | | Another example of a fascinating catfish |
| One of the most distinguishing anatomical | | | | species is the Candiru (Vandellia cirrhosa). |
| characteristics of the catfishes is the | | | | This catfish is popularly referred to as the |
| prominent barbells found near the mouth. A | | | | "Vampire Fish of Brazil" since it will attach |
| barbell is a long, tactile organ that is very | | | | itself to the gills of other fishes and drink |
| useful for fishes that live in murky waters | | | | their blood. This fish is not very popular in |
| where the visibility is limited. The catfish | | | | Southern America since it sometimes tries to |
| will use its barbells when hunting and | | | | attach itself to swimming humans, when |
| manoeuvring in dark environments, just like a | | | | attracted to blood or urine excretion. The |
| cat will uses its whiskers. The barbells of a | | | | body of this catfish is almost transparent, |
| catfish do however have taste buds and the | | | | which makes the fish quite hard to spot in |
| catfish can therefore "taste" its | | | | the water. The fish is also quite small, only |
| environment. You can find barbells on many | | | | 2.5-6 centimetres (1.0-2.4 inches) in lenght. |