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Amblydoras nauticus (Cope, 1874)  

Update: December 2009. You may have known this Dorad as Platydoras hancockii or Amblydoras hancockii but it has now been placed back to the Amblydoras genera as this species was misidentified, and is actually Amblydoras nauticus


his month (Sept.2005)
I am going back to a not too distant memory when I was lucky enough to take a fish catching trip to the Peruvian Amazon in 2000 and to attain a catfish that seemed to appear in every catchment net back then, the "Croaking Spiny Catfish", Amblydoras nauticus.

Amblydoras nauticus.


This species from the Doradidae family were very abundant in the Rio Orosa, a small tributary of the Rio Amazonas down the river from the city of Iquitos in Peru. We were catching very small juveniles about a ½ mile down this river in a small flooded cocha near the head of a small lake. The month was July and the waters were supposed to be quite low but were a bit higher than normal for this time of year. These catfish must have spawned a month or two earlier when the waters were higher and having received fresh cool water from the rising floods.

They can be quite variable in colour pattern as they are widespread in the Amazon region. Below can be seen one of my 6 sub-adults from this catchment. This fish was approximately 2 years old when photographed.

In common with most of the Doradidae family it can create a sound by grating its fin bones in each socket and amplifying the noise via the swim bladder which is one reason why it got its common name of
the “Croaking Spiny Catfish”


Amblydoras nauticus = sub adult

Again in common with most members of this family, they are easy to keep but are very secretive and you may not see them from one week to the next. I have found after a considerable time in captivity that they will venture out at spead to pick up any tasty morsels that is making its way to the substrate.

D 1/5; A 1/11; P 1/5. Dorsal fin-spine toothed on both anterior and posterior surfaces. Spinous scutes confined to the posterior half of the body. 3 pairs of barbels.

Brown body which is quite variable. Two black blotches, one below adipose fin and a large one at the caudal peduncle. Black line runs from caudal peduncle along body just below lateral line which stops posterior to the dorsal fin and takes a downward turn. Irregular spots and blotches to the head area.

No problem in a normal community tank as long as you can give them plenty of hiding places to make them feel more secure.

Sexual differences
It is said that the females underside is a dirty white colour whereas the males have a flecked pattern.

There are no known documented spawnings of this catfish in aquaria, but it is reported [Hancocki] that they construct a nest of leaves in the substrate and the eggs are laid during wet weather (flooded season), and once laid the eggs are covered with leaves. Both parents guard the eggs and emerging fry.

Good quality flake food, frozen blood worms and tablet food. Live worms such as whiteworm and cut up garden worms.

Amblydoras: Amblys= blunt; doras = leathery skin, cuirass.
nauticus : Named after the type locality, the town of Nauta, located on the north bank of the major Upper Amazonian tributary.

Glossary of Terms
Anterior - The head end.
- The tail end.
Scutes - Bony covering.
Swim Bladder - The air sac that gives fish buoyancy and balance. Acts as sound resonator in some fish.

Sterba, Gunther ; Freshwater Fishes of the World no.1
Catfish Study Group; Information Sheet no.15
Conservación Internacional; seris de Guías Tropicales De Campo. Pecos del medio Amazonas Región de Leticia. 546 p.

Photo Credits
Allan James @ ScotCat
Factsheet 111

Anadoras nauticus, Zathorax nauticus
Common Name:
Croaking Spiny Catfish, Marbled Talking Catfish.
South America: Upper Amazon River basin, Peru. Type locality: Nauta, (Upper Amazon).
Aquarium size:
24” x 12” x 12” (60 x 30 x 30mm)
7.5cm (3inch)
23-28°C (73-83°F)
6.5 - 7.5
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                                                                                                                          Factsheet 111 = updated December 14, 2018 , © ScotCat 1997-2018 Go to Top