Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Orthosternarchus tamandua

Orthosternarchus tamanduaOrthosternarchus tamandua
Photos by Andy Rapson


Orthosternarchus: Greek, ortho = straight + Greek, sternon = breast + Greek, archos = anus

General Notes:

Orthosternarchus tamandua is a shy, secretive and nocturnal species which is quite rare in the wild where little is known about it. They live in deep water and are almost blind but they do have a mildly electric field around them which may help them to navigate and hunt where visibility is very poor. The eyes of this species are asymmetrical and when viewed from above one eye is further forward than the other. In captivity they seem quite prone to bacterial infections from what little information there is. Because this is obviously such a specialised fish and that so little is known about it we recommend that it is not really a suitable subject for the aquarium.

Full description of Orthosternarchus tamandua


In the aquarium, reports suggest that Orthosternarchus tamandua is a very fussy eater and usually refuses all but small live food. Orthosternarchus tamandua has a very small tube like mouth and so small items of food are all that it could manage.


It isn't known if there are any visible differences between the sexes and nothing is known about this fish's breeding habits.


It has never been bred in captivity.

Wild status

Orthosternarchus tamandua is known to be quite rare in the wild but no studies about the health of wild populations have been carried out so the real status of this fish has not been evaluated.

Information at a glance

pH: 6- 7?
dGH: 4 - 12?
Temperature: 26 - 30°C (79 - 86°F)
Diet: Carnivore
Size: 44cm (17.5in)
Min tank size: 675 litres
Difficulty level: Do not keep
Aquarium type: Species
Swimming level: Lower

Distribution and habitat

distribution map for Orthosternarchus tamandua

Origin: South America: Amazon River basin, Brazil.

Habitat: Deep river channels away from shallow water. Orthosternarchus tamandua doesn't enter the flooded forest but remains in deep water. Found in both white water and black water


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gymnotiformes
Family: Apteronotidae
Genus: Orthosternarchus
Species: O. tamandua

Synonyms: Sternarchus tamandua.