The Fishes: Doradidae

SILURIFORMES - catfish - Page 1

Family: Doradidae

Family: Aspredinidae

Doradidae
The doradidae, or talking catfish, are characterized by possession of a series of plates along their sides. The dorsal fin normally comprises a strong spine and 6 rays. An adipose fin is present. Many species are able to make sounds ranging from grunts to clicks. There are about 36 genera within this family, which is in a constant state of revision. Members of this family are found in all Amazonian waters. The genera and species illustrated reflect the range of size and form within this family.

Acanthodoras	Agamyxis	Anadorus	Megaladoras
Opsodoras	Pseudodoras		Trachydoras

Acanthodoras
Two members of this genus, A. spinosissimus and A. cataphractus are well known to aquarists. They are generalist feeders that hunt for invertebrates at night and are noted for their sound generating abilities.

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Lateral view of a preserved specimen of Acanthodoras cataphractus	Lateral view of a recently caught specimen of Acanthodoras

Agamyxis
This genus holds two species, A. pectinifrons and A albomaculatus. The former, a nocturnal general predator which attains a maximum length of about 16 cm, is the best known by aquarists.

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View of the dorsal surface of Agamyxis pectinifrons	Lateral view of Agamyxis pectinifrons

Anadorus
This genus contains a number of widely distributed species. Anadorus grypus is particularly common in floodplain lakes and is often caught in floating meadow.

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Preserved specimen of Anadorus grypus

Megaladoras
The most characteristic feature of this genus is that the adipose fin is extended forward as a keel. M. irwini is one of the largest doradids, reaching a length of 60 cm. It lives within the floodplain where it feeds on snails.

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Lateral view of a preserved specimen of Megaladoras irwini

Opsodoras
This is one of the most species rich genera within the family with about 12 known species within the Amazon Basin. Diagnostic features include maxillary barbels with barblets, a dorsal spine with no serrations and an anal fin with a base little wider than that of the adipose fin. Opsodoras leporhinus is a common floodplain species.

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Lateral view of a preserved specimen of Opsodoras leporhinus	Dorsal view of a preserved specimen of Opsodoras leporhinus

Pseudodoras
This genus contains 2 or 3 species of which the best known and most common within the Amazonian flood plain is Pseudodoras niger.

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Preserved specimen of Pseudodoras niger

Trachydoras
There are about 4 species in this genus. A characteristic feature is the large size of the first lateral scute.

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Lateral view of a specimen of Trachydoras caught in the Amazon floodplain near Tefe

Auchenipteridae
This is a family of naked skinned catfish. They usually have three pairs of barbels, the lateral line often traces a zig zag line and the anal fin is usually long. The family comprises about 64 species divided between some 19 genera. A representative selection of some common floodplain species belonging to this family are illustrated in the following subsections.

Auchenipterichthys
This genus holds two morphologically similar, widely distributed species. Auchenipterichthys thoracatus is a common species in white water floodplain lakes where it hunts at night. Larger individuals, which can attain a length of 12 cm, feed on fish.

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Auchenipterichthys thoracatus viewed from the ventral side	Auchenipterichthys thoracatus viewed from the side

Auchenipterus
This genus holds three species characterized by their elongate, laterally compressed, form. The large eyes are positioned to look downwards. It has been suggested that there is actually only one valid species in this genus, the widely distributed Auchenipterus nuchalis.

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Auchenipterus nuchalis viewed from the dorsal side	Auchenipterus nuchalis viewed from the lateral side showing the downward looking position of the eyes	An unidentified Auchenipterus caught in lake Tefe

Centromuchlus
This genus holds two or three widely distributed species. A number of species previously placed in this genus are now placed in Tatia. These catfish are small with a rather torpedo shaped body which is broadest at the anterior. They are highly abundant in white water lakes where they live on the margins and within the roots of floating meadow. It is common when fishing with nets in floating meadow to catch many of these fish which become trapped in the mesh of the net by their long and very sharp dorsal spines. These spines can inflict painful wounds on the unwary.

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A preserved specimen of Centromuchlus heckelii viewed from the dorsal side	A preserved specimen of Centromuchlus heckelii viewed laterally. Note the tall and sharp dorsal spine

Epapterus
This genus holds about three species which are characterised by their elongate, laterally compressed form, large eyes and exceptionally long anal fin.

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Epapterus dispilurus viewed laterally	Epapterus dispilurus viewed from above

Parauchenipterus
This genus holds 11 or more species. They tend to be heavily pigmented with a head wider than it is high. They are abundant in floating meadow by day entering the open water of lakes by night to hunt.

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A common Parauchenipterus species of floating meadow viewed from above	A preserved specimen of Parauchenipterus

Aspredinidae
This family of small sized catfish is divided into two distinct subfamilies, the Aspridininae and the Bunocephalinae. The length of the anal fin distinguishes them, this is short in the Bunocephalinae and long in the Aspridininae. The head and anterior part of the body is broad and flattened while the tail is long and thin, forming an outline that is the basis for their common name of banjo or frying pan catfish.

Agmus

Bunocephalus

Agmus
Only the species Agmus scabriceps (now reclassified as Bunocephalus verrucosus) is known from the Brazilian Amazon. This species has a rough outline presumably to act as camouflage while resting on the bottom amongst wood and other debris during the day.

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Close-up of the head of Agmus scabriceps (Bunocephalus verrucosus)

Bunocephalus
There are about 20 species in this genus which is by far the best known genus within the family. They generally live in forest streams resting by day in leaf litter banks and amongst fallen wood.

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Dorsal view of Bunocephalus species