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hose of us that have been in the hobby for more years that we care to mention...may recognise this species from the Ariidae family of sea catfishes as, Arius seemanni, and later on as Hexanematichthys seemanni or by its favourite common name of the "Colombian Shark". These past scientific names were synonyms of Sciades seemanni but now we are back to a new genus name of Ariopsis. The Ariiidae family is ever changing and it is a difficult family to pin down as names are changing constantly once science has caught up with descriptions.

Ariopsis seemanni

MARCENIUK et al. (2007) in their paper, "Systematics of the family Ariidae (Ostariophysi, Siluriformes), with a redefinition of the genera" reclasified quite a few species in this family and also erected some new genera. They placed Arius seemanni in the Sciades genus as they are the largest number of ariid species from the eastern and western Americas, south and southeast Asia, southern New Guinea and northern Australia but as mentioned above it was moved later into Ariopsis.

Ariopsis seemanni

This is a peaceful species when young and small specimens are not a problem in aquaria but when they get bigger they can get restless and slightly more aggresive and will require a larger tank for swimming space and also a requirement for added salt as they grow into adulthood.

The problem as this fish grows is that it will require more salt and from a sub-adult brackish water system they will progress into a marine environment which will need marine salt to be added. Another problem of course is that your previous tropical tankmates will not be able to tolerate the added salt and would need to be moved to a tropical tank setup immediately. A juncture to this is that they can get aggresive as they mature so not really a catfish for the hobbyist unless you know what is ahead of you and you can maitain this species through the stages of tropical(juvenile) brackish (sub-adult) and adult (marine). This of course mimicks the lifestyle of this species in the wild as they migrate from the rivers of the Pacific coast countries of Mexico, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Ecuador and Peru and out into the sea where they can fend for themselves as large adults.

A large tank will be needed. 72inch or larger would be good for four adults. Growing plants will be difficult due to the added salt. Provide caves for hiding, a dark substrate and low lighting. They will also need good filtration with a swift current.

Shark Cat,, Jordans Catfish, Colombian Shark, Tete sea catfish.

Arius seemanni, Tachysurus seemani, Arius jordani, Hexanematichthys seemani, Sciades seemanni

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Western America: Mexico, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Ecuador and Peru. Type locality: Central America (Pacific).

35cm. SL (14ins) but can grow larger in the wild.

22-26°c (71-79°f)

7.0-8.0.

Broad head with a large mouth. The eyes are large and protrude from the head. Three pairs of barbels; one on the upper jaw and two on the lower.

Silver base colour on body with a white underside. Fins are black with white edges when young.

When young they can be combined with other brackish water fish such as Scats and Archer Fish. When adult they can be kept with other compatable sized Marine species.

Not been reported in aquaria. They are mouthbrooders where the male will brood them in his mouth. They will breed at the mouth of brackish estuaries.

Females are usually fuller in the girth than the slimmer males.

Omnivore, insect larvae, frozen foods such as mosquito larvae, tubifex and bloodworm. Tablet and flake foods are also taken.

Neurocranium: The portion of the skull surrounding the brain, including the elements that surround the olfactory, optic, orbital or sphenotic, and otic or auditory capsules and the anterior end of the notochord (endocranium) and the series of overlying dermal bones (dermocranium). Also called braincase.
Medial: Toward the middle or median plane of the body; opposite of lateral.
Otic capsules: Sensory anlage from which the ear develops; clearly visible during early development, also: the skeleton surrounding the inner ear or otic vesicle, composed of the prootic, opisthotic, exoccipital, and supraoccipital.
Transcapular process: Prefix meaning across.
Fontanel: A gap between bones in the skull, closed by a membrane, where ossification of cartilage or connective tissue did not occur. Commonly found on top of the skull between the frontal bones (anterior fontanel) and between the parietal bones (posterior fontanel),

Froese, R. and D. Pauly. Editors. 2009. FishBase. World Wide Web electronic publication.www.fishbase.org, version (10/2009).
Marceniuk, Alexandre P.; Menezes, Naércio A. (2007). "Systematics of the family Ariidae (Ostariophysi, Siluriformes), with a redefinition of the genera" Zootaxa 1416: 1–126.
Mongabay

Photo Credits

Image credits: Bill McBurnie