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Plotosus lineatus (Thunberg, 1787)

he theme for this catfish of the month (May 2007) is "Look, but don't touch" which tells you a little bit about this member of the Plotosidae family.

This is the first factsheet that does not encompass a freshwater species as the "Coral Catfish" lives in the open ocean and thus in a saltwater situation. The "Look but don't touch" mantle refers to the very venomous spines in their dorsal and pectoral fins and Burgess (1989) and Nelson (1994) state that their stings might be fatal in some circumstances.

If you do succumb to a sting from this catfish you need to first thrust your hand into hot water as hot as you can stand it to heat the poison up and so hopefully dilute it, and then you may have to make a trip to your local hospital if things get worse. Best to have someone around when working with this fish.

Plotosus lineatus

In their natural habitats they school in a group looking for food so if purchasing you must not buy them singularly but in a group of between 5 and 8. The freshwater species of the Plotosidae family can be bought as individuals but not this saltwater cousin as they will sulk and waste away.

When very young they are mostly black and when they start to mature the white to yellow ventral stripes begin to appear gradually to make this catfish a real beauty to the enthusiast. It is only when they get to the adult stage that they lose this trait and revert to a murky brown colour.

The close up image below shows the barbel arrangement of this species.



Plotosus lineatus = showing the barbel arrangement

Plotosus lineatus are easy to keep in captivity as long as you can purchase a group free of any parasites as they don't like copper based medications in the aquarium and it is better to drop the salinity of the water gradually if you spot any problems with diseases, to basically give them a freshwater dip.

The size of a group of this species necessitates that you house them in a large aquarium, starting of with a 4ft tank for juveniles working your way up to a 8ft x 2ft x 2ft tank for a small group of adults. The life span is reputedly 7 years.

A tank set-up for them would comprise of a sand/gravel or coral/rock rubble, which can be aggregated in flanks or balls on sandy bottoms. A good water current is preferred with hiding places in the aquarium. A good quality salt mix (pre-mixed for a day before use) of a constant high or low range salinity is fine. The pH values would need to be monitored with the heavy feeding that is common with these cats.

Dorsal 1/4-5; combined fin 80-100/~10-70-80; Pectoral 1/10-11; Ventral 11-12. Body elongate, torpedo shaped, compressed. Head large. The second dorsal combines with the caudal and anal to form a uniform fringing fin. 4 pairs of short barbels.

Upperside dark brown to blackish, becoming fawn towards the belly which itself is delicate brown to yellowish. Young fishes with 2 (-3) striking pale, yellowish to bluish-white, longitudinal stripes. Fins brown, the combined fin often dark edged.


Can be kept with other Marine fish of compatible size but larger adults would be best kept on their own. Can be kept with invertebrates when young but could pose a problem for them when they get larger.


In their natural habitat they lay their eggs in nests constructed by the males in shallow, rocky areas in the summer months.

There have been reported spawings in the home aquarium as well as in Public Aquaria.

Sexual differences
Not known.

No problem in this department as they will greedily feed on pellets, marine flake, frozen and fresh food. Two daily feedings of at least one of defrosted frozen food will suffice.

Glossary of Terms
Dorsal : The primary rayed fin(s) on top of the body
Pectoral: The paired fins after head and before anal fin.
Anal Fin: The fin forward from the anal cavity.

Plotosus = Plotos = swimming.

lineatus= Lined or streaked.

Fenner, Robert; Look, but don't touch!, Marine Catfishes of the Family Plotosidae. Tropical Fish Hobbyist, July 1996.
Dakin, Nick; Bats & Cats. Fishkeeping Answers, November 1993.
Sterba Günther; Freshwater Fishes of the World Vol.1

Photo Credits

©  Johnny Jensen's Photographic Library

Factsheet 131

Silurus arab, Silurus lineatus, Platystacus anguillaris, Plotosus anguillaris, Plotosus thunbergianus, Plotosus  marginatus, Plotoseus ikapor, Plotosus vittatus, Plotosus castaneus, Plotosus castaneoides, Plotosus arab, Plotosus flavolineatus
Common Name:
Coral Catfish



Indo-Pacific: Red Sea and East Africa to Samoa, north to southern Japan, southern Korea, and the Ogasawara Islands, south to Australia and Lord Howe Island. Palau and Yap in Micronesia.
30cm. (12ins)
24-26°C (75-79°F)    
8.0 -8.5.
Ammonia & Nitrite
Less than 20ppm
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                                                                                                   Factsheet 131 = updated May 22, 2019 , © ScotCat 1997-2019 Go to Top