Synonyms: Arius jordani, Hexanematichthys seemani, Tachisurus seemani STYLE="mso-bidi-font-style : normal ; mso-spacerun : yes"> STYLE="mso-bidi-font-style : normal ; mso-spacerun : yes">
Physical description: The body is elongated and silver in color and the belly is white. The fins are black and white-tipped. The head is broad, with a large mouth. The eyes are large and protrude from the head. The Shark Catfish possesses three pairs of barbels; one on the upper jaw and two on the lower. The color contrasts fade with age.
Size/Length: To 24" (60 cm) in nature, although rarely larger than 15" (38 cm) in captivity.
Similar species: Other Arius species
H: North, Central, and South America; estuaries of tidal rivers and lagoons from Southern California to Peru on the Pacific Coast
A: bottom, middle
Aquarium: A 40" (102 cm) or 45-55 gallons (170-209 L) is sufficient for young individuals. Adults need a tank of at least 64" (163 cm) or 100-125 gallons (378-472 L). The tank should be well lighted, maybe in a position to receive morning sun. A strong filter is necessary for a powerful current and a good turn-over rate. Provide many caves and hiding places.
Water chemistry: pH 6.8-8 (7.6), 8-30 dH (16), 72-81°F (22-27°C). A 2% addition of salt is necessary. This can be accomplished by adding 15 TSP. of salt/ 10 gallons (20 g of salt/10 L).
Social behavior: Combine only with larger, sturdy fish who live in brackish water. These fish are capable of swallowing fish up to 67% of their length. Keep in groups of four or more individuals.
Social behavior: Adults can be combined with marine species; young can be combined with Anableps, Monodactylus, Scatophagus , Tetraodon , and Toxotes species.
FOOD: Live; fish, crustaceans, insect larvae; tablets. This species prefers food in chunks. Has huge appetite and may attack other tank mates if not fed sufficiently.
Suggested companions: Females plumper when over 12" (30 cm).
Breeding techniques: Unsuccessful in captivity because of the area needed. Spawning has been observed in nature. It takes places in freshwater and brackish estuaries. Up to 100 marble-sized eggs are mouth-brooded by the male.
Breeding potential: 10. Breeding has not been accomplished in aquaria.
Remarks: A very active fish. Can only be kept in fresh or brackish water while juveniles. With age more salt must be added to the water. Adults require sea water or brackish water. Some populations of this fish migrate south from California during the colder parts of the year. By rotating its pectoral fin in its socket, adult fish can make a loud, croaking sound. This sound is amplified by the swim bladder.
Difficulty of care: 4 (while young). Young fish are extremely hardy, but aggressive and require live foods. 7 (adult). Adults need to be kept in salt water, and are highly aggressive towards smaller fish.
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