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Akysis portellus Ng, 2009


he Akysidae family include small and miniature species which are sexually mature when only 3cm. They are characterised by their short dorsal fin with a sharp spine, a distinctive adipose fin, and a broad based barbel developed on the posterior nostril.


Akysis portellus


Akysis portellus

Akysis portellus is most similar to A. longifilis, which occurs sympatrically in the Sittang River drainage. It is distinguished from A. longifilis in having a shorter adipose-fin base, smaller mouth and a more rounded head shape when viewed dorsally.




Akysis portellus - dorsal head view


Type localities of Akysis portellus (triangle) and A. longifilis (circle)



All species in this genera possess a venomous apparatus at the base of the dorsal and pectoral spines and though not dangerous to a healthy human can inflict a painful sting, so should be handled with care when being removed from the water for any reason or during aquarium maintenance.


Like other members of its genera, an aquaria having a sand substrate interspersed with small rocks and pebbles mixed with thick clumps of plants would suffice. Unless feeding, when they are highly active, they can be over looked in aquaria that has a sand substrate as they like nothing better than to bury themselves, leaving only their nasal barbels which protrude slightly from the sand to indicate where they are. So the next time you see a tank labelled ‘Akysis’ and there appears to be an empty tank, check the substrate to see if you see any barbels protruding out of the substrate.




Dorsal spines (total): 1; Dorsal soft rays (total): 4-5; Vertebrae: 32 - 33. It is distinguished from A. longifilis in having a shorter adipose-fin base, smaller mouth and a more rounded head shape when viewed dorsally.

In ethanol: dorsal surface and sides of head medium grayish brown with few darker brown spots randomly scattered throughout. Dorsal surface and sides of body dark grayish brown. Belly, chest and ventral surface of head and body light brown. Dorsal half of body with two elongate saddle shaped light brown spots: first on body at anterior three-quarters hue over dorsal surface of head and body.

Aquarium Care

These are ideal catfish for the smaller sized aquarium. Not difficult to keep but should really be provided with a soft, sandy substrate since some of its time is spent completely buried, or with only eyes protruding. It also appears to enjoy squeezing into crevices between rockwork and other solid surfaces so additional decor could include some water-worn rocks of various sizes, plus perhaps some driftwood roots and branches.



Fish like barbs and rasbora’s make excellent tank mates, however as they have quite wide mouths, any fry from livebearers or fish around that size would be readily predated upon.



There have been reports of their spawning, but as yet there are no reports of fry development. Several males were observed with A. vespa where the male was in pursuit of a gravid female, and the successful individual was allowed to wrap its body around that of the female at which point eggs and milt were released. The eggs hatched 4 days post-spawn with the yolk sac fully-absorbed after 10 days. Adult patterning was fully-developed after just 23 days.

Sexual Differences

Sexing is relatively easy with the female having larger ventral and pectoral fins.



Feeding does not cause any difficulty, as long as you use frozen or live foods such as bloodworms, brine shrimps, white worms and daphnia, as they tend to ignore commercially prepared foods.

Glossary of Terms

Dorsal spines: The primary rayed fin(s) on top of the body
Adipose fin: Fleshy finlike projection without rays, behind the rayed dorsal fin.
Pectoral fin: The paired fins just behind the head.


Akysis: A = without; kysis = bladder, in reference to the lack of a swimbladder

portellus: From the Latin portella, the diminitive form of porta, meaning door. The name is used as a noun and alludes to the relatively small mouth of this species.


Ng, H.H., 2009. Akysis portellus sp. Nov., a new species of catfish (Teleostei: Akysidae) from the Sittang River drainage, Myanmar. Journal of Threatened Taxa 1(1):2-8
Froese, R. and D. Pauly. Editors. 2017.FishBase. World Wide Web electronic publication. www.fishbase.org, ( 06/2017 )
Wheeler, Alwyne., Fishes of the World - an Illustrated Dictionary. Ferndale Editions London. 1975. 366p.
Taylor, Adrian., http://www.scotcat.com/factsheets/akysis_prashadi.htm

Photo Credits

Johnny Jensen ©  Johnny Jensen's Photographic Library

Steven Grant; http://www.scotcat.com/akysidae/akysis_portellus4.htm

Factsheet 255

Common Name:
Asia: Myanmar. Known from the type locality in the Sittang River drainage, southern Myanmar. Type locality: Shwe Kyin stream, a minor tributary of the Sittaung (aka Sittang) River system in Bago (formerly Pegu) Region, southern Myanmar.
3.5cm (1½ins) 
18-22°C (63-71°F)
6.5 - 7.5.
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