Tetra is the common name of many small freshwater characiform fishes. Tetras come from Africa, Central America, and South America, belonging to the biological family Characidae and to its former subfamilies Alestidae and Lebiasinidae. The Characidae are distinguished from other fish by the presence of a small adipose fin between the dorsal and caudal fins. Many of these, such as the neon tetra, are brightly colored and easy to keep in captivity. Consequently, they are extremely popular for home aquaria.
Hyphessobrycon is a genus of freshwater fish in the family Characidae. These species are among the fishes known as tetras. The genus is distributed in the Neotropical realm from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about six species are from Central America and a single species, H. compressus is from southern Mexico.
Telescopefish are small, deep-sea aulopiform fish comprising the small family Giganturidae. The two known species are within the genus Gigantura. Though rarely captured, they are found in cold, deep tropical to subtropical waters worldwide.
The rainbowfish or Melanotaeniidae is a family of small, colourful freshwater fish found in northern and eastern Australia, New Guinea, Sulawesi and Madagascar.
The harlequin rasbora is a small fish in the family Cyprinidae. The species became an instant favorite among aquarists after its introduction in the early 1900s and is the best known and most widely kept species among the rasboras. In 1935, an image of a trio of harlequin rasboras, stamped in 14k gold, would grace the cover of the first edition of William T. Innes's classic Exotic Aquarium Fishes and would remain so through all 19 editions.
This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes.
The lemon tetra is a species of tropical freshwater fish which originates from South America, belonging to the family Characidae. It is a small tetra growing to 5 cm in length. The species is a long established favourite aquarium fish, being introduced to the aquarium in 1932.
The rummy-nose tetra is a species of tropical freshwater characin fish originating in South America, popular among fishkeepers as a tropical aquarium fish. One of many small tetras belonging to the same genus, it is on average 5 cm (2 in) long when fully grown. The fish is one of several very similar species including Hemigrammus bleheri, and Petitella georgiae, and it is possible that more recently collected specimens available in the aquarium trade are members of one or other of these similar species. The common name applied to most of these fishes is "rummy-nose tetra", though other common names are in circulation.
The balloon shark is a species of catshark, and part of the family Scyliorhinidae, endemic to the southwestern Indian Ocean off South Africa and Mozambique. Benthic in nature, it is found over sandy and muddy flats at depths of 40–600 m (130–1,970 ft). This thick-bodied species has a broad, flattened head and a short tail; its distinguishing traits include narrow, lobe-like skin flaps in front of the nostrils, and a dorsal color pattern of faint darker saddles on a light grayish background.
The Izak catshark or simply Izak is a species of catshark, belonging to the family Scyliorhinidae, common off the coasts of South Africa and southern Namibia. It typically inhabits the outer continental shelf at depths of 100–300 m (330–980 ft), with the males found deeper than the females and juveniles. The Izak catshark has a short, wide, flattened head and a robust body tapering to a long, slender tail. It can be identified by its ornate color pattern of dark brown spots or reticulations and blotches on a light yellowish background, as well as by the enlarged dermal denticles over its pectoral fins and along its dorsal midline from the snout to the second dorsal fin. This species reaches 69 cm (27 in) in length, with the males larger than females.
Pelvicachromis pulcher is a freshwater fish of the cichlid family, endemic to Nigeria and Cameroon. It is popular amongst aquarium hobbyists, and is most commonly sold under the name kribensis, although it has other common names, including various derivatives and color morphs of the kribensis: krib, common krib, red krib, super-red krib and rainbow krib, along with rainbow cichlid and purple cichlid.
The longfin sawtail catshark is a rare, little-known species of catshark, part of the family Scyliorhinidae. Once thought to be a subspecies of the roughtail catshark along with the Antilles catshark, it inhabits deep water off the Caribbean coasts of Panama and Colombia. This slim-bodied species has a marbled dorsal color pattern and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. It can be distinguished from similar species by its relatively longer anal fin and small adult length of under 35 cm (14 in). The longfin sawtail catshark is oviparous.
The broadfin sawtail catshark is a common species of catshark, part of the family Scyliorhinidae. It is found on or near the bottom at depths of 150–540 m (490–1,770 ft), from southeastern Japan to the East China Sea. A slender species growing to 68 cm (27 in) long, this shark is characterized by a fairly long, pointed snout, a series of indistinct, dark saddles along its back and tail, and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. In addition, adult males have very long claspers that reach past the anal fin. The broadfin sawtail catshark is an opportunistic predator of bony fishes, cephalopods, and crustaceans, with immature and mature sharks being primarily piscivorous. It is oviparous and reproduces year-round.
The peppered catshark is a common but little-known species of catshark, part of the family Scyliorhinidae, inhabiting depths of 130–1,326 m (427–4,350 ft) in the northern Gulf of California. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of 37 cm (15 in), this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its caudal fin is a prominent crest of enlarged dermal denticles. It is oviparous, with the reproductive period probably lasting from May to September. The International Union for Conservation of Nature (IUCN) has listed the peppered catshark under Least Concern, as it faces no significant threats from human activity.
The African sawtail catshark is a species of catshark, part of the family Scyliorhinidae. Demersal in nature, it is found at depths of 160–720 m (520–2,360 ft) off the western African coast from Morocco to South Africa. This slender species has a rather long, pointed snout, a series of dark saddles along the back and tail, and a prominent crest of enlarged dermal denticles along the upper edge of the caudal fin. Its maximum known length is 46 cm (18 in).
Hemigrammus is a genus of freshwater fish in the family Characidae native to South America and commonly seen in the aquarium trade. These are medium-small tetras where the largest species reach up to around 11 cm (4.3 in).
Iguanodectes is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry. Alongside the genus Piabucus, it is in the subfamily Iguanodectinae, which in turn is in the family Iguanodectidae. The genus Bryconops, which is also in Iguanodectidae, makes up a sister clade to Iguanodectinae.
Pyrrhulina is a genus of freshwater fishes found in tropical South America. Several of these species are popular aquarium fish.
Copella arnoldi, commonly known as the splash tetra or the splashing tetra, is a species of tropical freshwater fish belonging to the family Lebiasinidae. It is native to South America.
Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes. Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras. There is minor, but ongoing, debate regarding its taxonomy.
