There's a good chance it's a Characin... if you see a freshwater fish with an adipose fin and no barbels!
Characins are very large group of fish that make up the Order Characiformes. There are at least 1674 species contained in about 270 genera.
A visual clue to a Characin is that it will have an adipose fin. That's the little fin on top behind the dorsal fin and just before the tail. What its purpose is remains a mystery, but many Characins except for a few genera have them. An adipose fin can also be found on several catfish types.
Some other clues to identifying Characins are that, unlike catfish, they don't have any barbels. Barbels are whiskers or antennae type extensions that extend from around the mouth area of some fish. The Characins are also primarily freshwater fish and are most primarily carnivorous, eating proteins of various sorts. But many will also eat some plant matter, so are actually actually omnivores. Of those that are herbivorous Characins, some are Limnivores, ("mud-eaters" or "bio-film grazers"). These fish eat algae, microorganisms and other things growing on the rocks and substrate of their environment.
Characins are generally hardy fish and many are great for the beginner. Most are schooling fish so they do better in a community aquarium with lots of buddies to hang out with. Apart from the predatory species such as the Piranhas, most are peaceful even if carnivorous. They will usually readily accept aquarium foods like flakes and tablets, as well as enjoying supplements of brine shrimp and various types of worms. They usually prefer clear, slightly acidic water with strong currents and highly oxygenated. This can be provided with a strong filter and good surface movement.
The Characin species list below includes popular types, as well lesser known Characin varieties. Each fish guide has a description of the species, its place of origin, habitats and behaviors, as well as fish care to successful maintain them in an aquarium. Fish pictures are also provided within each fish guide to help with identification, and to aid in choosing the best type of Characin for your freshwater fish tank.
- Other Characin Fish (Silver Dollar, Headstander, Leporinus)
For Information on keeping freshwater fish, see:Freshwater Aquarium Guide: Aquarium Setup and Care
Other Characin Fish
What are Characins
Some of the best known Characins are the brightly colored Tetra species. Yet this group has great diversity in size, shape, and behaviors. Fortunately many members are under 1 1/4 inches (3 cm) so are great for smaller aquariums. Shapes range from round disc-type' fish like the Silver Dollar, elongated fish like the Pencilfish, to the Hatchetfish with a deep bodied 'hatchet' type shape. And behaviors are of all sorts. The Hatchetfish for example, are known to break the surface of the water and "fly" after their prey using their large pectoral fins as "wings"!
Characins are found in Central America, South America and Africa. They are considered by some to be the most ancient fishes in the Superorder Ostariophysi. They are members of the Order Characiformes, one of four orders contained in the Ostariophysi superorder. Their three sister orders are the Cyprinids of the Order Cypriniformes containing minnows and allies, the Catfish of the Order Siluriformes, and the Electric Eels and American Knifefish of the Order Gymnotiformes.
There are at least 1674 Characin species contained in about 270 genera. The fact that they are in both the Americas and Africa is considered proof that the two global continents were once joined! This means that Characins originated before the land masses split in Mesozoic times, some 80 to 150 million years ago. Currently there are about 1465 species in the Americas and about 209 species in Africa along with many species that are not yet discovered.
Characins are a large group of fish with a great diversity in size and shape. They range in size from the tiny Bolivian Pygmy Blue Characin, Xenurobrycon polyancistrus at just over 1/2 inch, 0.67" (1.7 cm) to the gigantic Goliath Tigerfish Hydrocynus goliath at 4 1/3 feet (1.3 m). A few of the larger characins are important as food or game fish. Shapes range from round disc-type' fish like the Silver Dollar, elongated fish like the Pencilfish, to the Hatchetfish wiht a deep bodied 'hatchet' type shape.
Taxonomy of Characins
Taxonomically the Characins used to be contained in a single family, Characidae, under the Characiformes order. But there has been all sorts of systematic and taxonomic changes in recent years. Many species have been separated into their own families, so now there are 18 recognized Characiform families including the Characidae family. Those that remain in the Characidae family, about 776 species, are now more commonly referred to as characids, with the term "characin" still reflecting the entire order of Characiformes.
Anatomy of Characins
Characins resemble Cyprinids but they have an adipose fin located between the dorsal fin and tail. This fin is small, fleshy, and lacks the rays usually found in the other fins. They are carnivores with teeth in a mouth that is usually not protractile, meaning it is not capable of extending forwards such as on sucker mouth types of fish. The bodies of most species are covered in well-defined scales.
Anatomically Characins have the characteristics of each group of their descending taxonomic hierarchy.
- Class: Actinopterygii
Characins are members of the Actinopterygii Class of "ray-finned" fishes. They are characterized by having fins that are webs of skin supported by bony or horny spines.
- Subclass: Neopterygii
As a member of the Subclass Neopterygii, the "new fin" species are distinguished from their ancestors by being able more faster, their scales and skeletons became lighter, and their jaws became more powerful and efficient.
- Infraclass: Teleostei
As a member of the Infraclass Teleostei, they have modifications to the jaw that allows them to protrude their jaws outwards from the mouth, the upper and lower lobes of the tail fin are about equal in size, and their spine ends at the caudal peduncle.
- Superorder: Ostariophysi
Characins possess a Weber's apparatus, a characteristic of all fish in the Ostariophysi Superorder. This is a series of bony parts that connect the hearing organ with the swim bladder where it operates as a sounding board, thus amplifying sounds.
There are 18 Characin families recognized plus one other, Triporthidae, that was raised from the status of a sub-family to family. There is also Serrasalminae that is currently classified as a subfamily of Characidae, but some place these fish in their own family Serrasalmidae. Below is a list of Characin Families and details about each:
Characin - Order: Characiformes
|Acestrorhynchus are "needle jaw" fish referred to as Freshwater Barracuda in the aquarium trade. These fish have elongate pike-like bodies and large conical teeth, adapted for predation on other types of fish. They range in size from about 1 1/3 to 15 3/4 inches (35-400 cm) in length.||South America||1||14|
|Alestidae, or Alestiidae, contains African Tetras, Robbers and Tiger Fish including the well-known Congo Tetra, and African Tigerfish. The largest species reach a maximum size of about 41 inches (104 cm) in length.||Africa||18||109|
|Anostomidae||Anostomidae are Headstanders with elongated bodies and range in size from 5.9 - 24 inches (15-60 cm) in length. Most species are herbivores or detritivores. They typically swim in a head-down posture feeding plants, detritus and invertebrates.||South America||14||140|
|Characidae||The Characidae family inhabits a wide range and variety of subtropical and tropical habitats. Originally this family contained all the members of the Characiformes order, however many were recently moved to other families.|
North, Central and South America
|The Serrasalminae contains the Pacu, Piranha, and Silver Dollar. It is currently classified as a subfamily of Characidae. Some place these fish in their own family Serrasalmidae, but the taxonomy and systematics of these fish is very complicated and much remains unsettled.|
|Chilodontidae||Chilodontidae are small Headstanders with elongated bodies with colorful markings and are distinguished by a habitual head-down posture. All species are less than 2.8 inches (7 cm) in length.||South America||2||7|
|Citharinidae||Citharinidae are filter-feeders known as "lutefish". They are deep-bodied silvery colored fish that is a significant food fish for natives in Africa. They can reach up to 33 inches (84 cm) in length and weigh up to 40 lb (18 kg).||Africa||3||6|
|Crenuchidae||Crenuchidae are South American Darters. They are relatively small fish, usually with a body length under 4 inches (10 cm).||Central and South America||3||6|
|Ctenoluciidae||Ctenoluciidae are predatory fish referred to as Freshwater Needlefish or Freshwater Barracuda in the aquarium trade. These fish have elongate pike-like bodies and sharp, conical teeth. They are relatively large reaching up to 3 1/3 feet (100 cm) in length.||Central and South America||2||7|
Curimatidae are known as Toothless Characins. They are limnivores or "bio-film grazers" that can reach up to 12.6 inches (32 cm) in length.
|Cynodontidae||Cynodontidae is a small family of characins known as the or Dogteeth Tetras. They range in size with the smallest being about 7 3/4 inches (20 cm) and the largest species reaching up to 26 Inches (65 cm). These fish are carnivores adept at preying on fish with elongated, well-developed canine teeth. Some species are game fish pursued for sport by recreational anglers.||Central and South America||5||14|
|Distichodontidae||Distichodontidae consists of both herbivores and those that prey on very small organisms, referred to as micropredators. They range in size from less than 3.1 inches (8 cm) in length up to 33 inches (83 cm).||Africa||17||90|
|Erythrinidae||Erythrinidae fish are cylindrical in shape with blunt heads and can reach up to 35 inches (90 cm) in length. They are game fish pursued for sport by recreational fishermen.||Central and South America||3||16|
|Gasteropelecidae||Gasteropelecidae are a small family of the well-known hatchetfish. They are very distinctive with their hatchet-shaped deep body and long pectoral fins. They generally swim directly below the surface of the water and use their pectoral fins to "jump' from the water and glide along the surface for short distances.||Central and South America||3||9|
|Hemiodontidae||Hemiodontidae are Characins known as Halftooths. Most species have a round spot on each side in the middle of the body and a stripe along the bottom of the tail fin. They are elongated streamlined fish and fast swimmers. Many can jump from the water to escape predators.||Central and South America||9||29|
|Hepsetidae||The Hepsetidae family contains the African Pikes.||Africa||1||2|
|Lebiasinidae||Lebiasinidae family contains the Pencilfish and the Splashing Tetra. These are very pretty ornamental aquarium fish with elongated cylinder shaped bodies and range in size from .79 to 2.8 inches (2-7 cm) in length.||Central and South America||7||67|
|Parodontidae||Parodontidae consist of fish found in mountain streams known as Scrapetooths. They generally don't exceed 5.91 inches (15 cm) in length.||Central and South America||3||32+|
|Prochilodontidae||Prochilodontidae family is a small family known as the Flannel-mouthed Characins and are known to make an audible grunting noise. They live in huge schools and the largest species can reach up to 31 inches (80 cm) in length. They are a popular food fish.||South America||3||21|
|**Triporthidae||Triporthidae family was raised from the status of a sub-family to family and contains the Elongated Hatchetfish.||Central and South America||4||23|