The Fishes: Sciaenidae

PERCIFORMES - perches & cichlids

Family: Sciaenidae

Family: Cichlidae

Sciaenidae
This is a large mainly marine family known as croakers or drums because of the sounds they make. Two species particularly common in the Amazonian floodplain are Pachypops furcraeus and Plagioscon squamosissimus. They are both able to produce sound with their swim bladders and are open water predators.

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Pachypops furcraeus - Lateral view. Note the structure and position of the mouth	Photograph of two freshly caught Plagioscon squamosissimus. Note the characteristic and highly visible lateral line. These individuals were caught in a black water lake

Cichlidae
This is one of the commonest families within the floodplain. It includes many well-known aquarium fish such as the discus and angelfishes. Cichlids are particularly abundant in structurally rich habitats such as regions with fallen trees or floating meadow. They are rarely found in open water. They are perch-like fish with only a single nostril on each side of the head.

Acaronia	Aequidens	Apistogramma	Astronotus	Cichla
Crenicichla	Geophagus	Heros	Mesonauta	Pterophyllum
Symphysodon

Acaronia
These species are related to the genus Aequidens, from which they differ in having a larger mouth.

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Acaronia nassa - Lateral view of specimen caught in Lago Mamiraua amongst floating meadow

Aequidens
A genus of medium sized cichlids characterized by having gill arches without lobes, small gill rakers, scales along the lateral line the same size as other scales and all teeth of approximately equal size. Aequidens tetramerus is one of the commonest species in floodplain floating meadow.

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Lateral view of an adult Aequidens tetramerus

Apistogramma regani, Kallender 1980
Identification: Within the litter banks of the Taruma-Mirim this species is the only member of the genus Apistogramma. There are a large number of species within this genus and we cannot be sure we have identified the species correctly. However, it generally conforms to the species description and A. regani is known from this region of the Rio Negro. A typical dwarf cichlid, this species is small ( adult length 5 cm), there is a dark band running along the body and a number of ill-defined vertical bars. The mature male carries a number of iridescent blue dots on the operculum and around the eye.
Habitat: Litter-banks in regions holding whole leaves.
Abundance: One of the commonest litter-bank fish. Average densities within litter banks of the Taruma-Mirim were 8.84 individuals per sq.m. In favoured areas, densities can reach 150 individuals per sq m.
Food: General predator feeding on small insects, particularly chironomids.

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Photograph of an adult Apistogramma species caught in a litter bank in a blackwater stream	Lateral view of an Apistogramma species caught in forest streams	Lateral view of an Apistogramma species caught in floating meadow

Astronotus
There are two species within this genus, one of which, Astronotus ocellatus, is well known to aquarists as the oscar. This is a medium to large sized cichlid which can make a fine pet. It is regularly eaten in the Amazon. It is a common species in white water floodplain lakes.

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Lateral view of a preserved specimen of Astronotus ocellatus, the oscar	Juvenile Astronotus ocellatus

Cichla
This genus holds two large, predatory cichlids, Cichla ocellaris and Cichla temensis. They are an important food fish and are also sought after by anglers. They live in both blackwater forest streams and floodplain lakes. Adults are territorial usually occupying an area of bank which includes some structure such as a fallen tree. Here they will lurk waiting to attack any unwary fish that ventures too close. They will willingly attack spinners that are cast into their territory. The eggs are usually attached to submerged wood that is carefully cleaned beforehand.

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A fine specimen of Cichla monoculus, known locally as the tucanare

Crenicichla
These are long-bodied predatory cichlids, commonly called pike cichlids. There are numerous species and the genus is found in most Amazonian waters. The dorsal fin is extremely long.

Crenicichla notophthalma Regan (Crenicichla dorsocellatus)
Identification An elongate cichlid with a characteristic 'eye spot' on the dorsal fin. All of the individuals caught within the Taruma-Mirim are small (typically 5-7 cm total length). C. notophthalma are now considered to be the juveniles of C. dorsocellatus.
Habitat: Litter-banks in regions holding whole leaves.
Abundance: One of the commonest litter-bank fish. Average densities within litter banks of the Taruma-Mirim were 1.1 individuals per sq.m. In favoured areas densities can reach 20 individuals per sq m.
Food: General predator feeding on insects, prawns and small fish.

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An adult Crenicichla species caught in a blackwater floodplain lake
Crenicichla notophthalma (Crenicichla dorsocellatus) photographed following capture in a litter bank	A small Crenicichlid species caught in submerged leaf litter	A small Crenicichlid species caught in submerged leaf litter

Geophagus
The taxonomy of this group is confused. They are related to Apistogramma, but are generally larger fish with a distinctive high outline to the head.

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A catch of Geophagus proximus taken by local fishermen

Heros
This genus is now considered part of Cichlosoma. We retain it here because the situation is still rather unclear and Heros appendiculatus is a familiar species.

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A living adult Heros appendiculatus photographed following capture in a white water floodplain lake

Mesonauta
There are two species of Mesonauta. Members of this genus are abundant in Amazonian floodplain lakes where they can be seen moving through shallow water and along the banks in small groups. The individuals in these groups align themselves to each other to form a defensive circle.

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Mesonauta insignis - Lateral view of freshly caught specimen

Pterophyllum
This is the genus of the famous and familiar angelfishes. This genus is immediately recognizable by its distinctive shape. It is adapted for moving between plants and is found in flooded forest and amongst fallen trees. There seem to a number of species although the situation will not be fully understood until molecular studies are completed.

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Lateral view of Pterophyllum scalare caught in a floodplain lake at low water

Symphysodon
This is a small genus of species that are disc shaped and specialized for moving between plants and fallen trees. They are usually found in flooded forest and lakes in areas where trees have died and fallen over. The taxonomy of the group is confused and it is difficult to identify individuals to species.

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Photograph of a preserved specimen of an adult Symphysodon aequifasciatus caught in a white water floodplain lake