CYPRINIFORMES - carps and characins: Page 3

  • Family: Hemiodontidae
  • Family: Lebiasinidae

    Hemiodontidae
    A family of characiform fish characterized by their reduced dentition, with most species lacking teeth in the lower jaw. They are generally elongate, round-bodied fish with silver bodies and patterned tails. The family presently holds 33 species, which are distributed throughout the Amazon basin and Orinoco river and as far south as the River Parana. These species are divided between 5 genera, Anodus, Micromischodus, Argonectes, Bivibranchia, and Hemiodus.

    Hemiodus
    is the most species rich genus of the Hemiodontidae and now includes species previously assigned to Anistsia, Hemiodopsis and Pterohemiodus. Typically, these are elongate, open water fish that are fine swimmers that will readily jump clear of the water. These fish require well oxygenated water and thus are one of the first species to die during periods when the surface oxygen in white water lakes falls to low levels.
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    Two recently caught specimens of Hemiodus immaculatus. This species is common in Amazonian floodplain lakes
    Two recently caught specimens of Hemiodus immaculatus. This species is common in Amazonian floodplain lakes

    Two recently caught specimens of Hemiodus microlepsis. This species is common in Amazonian floodplain lakes. Note the red and black markings on the lower lobe of the tail
    Two recently caught specimens of Hemiodus microlepsis. This species is common in Amazonian floodplain lakes. Note the red and black markings on the lower lobe of the tail

    Lebiasinidae
    Small members of the charciformes normally without an adipose fin, they have a small mouth set at the end of the head. Common species include Pyrrhulina sp., Copella cf. arnoldi, Copella nattereri group, Nannobrycon eques, Nannobrycon unifasciatus, Nannostomus cf. harrisoni, Nannostomus trifasciatus and Nannostomus marginatus. (It should be pointed out that Nannobrycon were previously placed in the genus Nannostomus). They often take the head standing attitude.
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    Copella species caught in floating meadow in a whitewater lake near Tefe
    Copella species caught in floating meadow in a whitewater lake near Tefe

    Pyrrhulina laeta
    Identification: A typical member of the Lebiasinidae - small upturned mouth, large scales, and a dark horizontal line through the eyes. This species is considerably larger and more deep bodied than Copella nattereri, which is the only other species living within the Taruma-Mirim with which it might be confused.
    Colour: Silver background with yellow tinge to fins; dark line along anterior mid-line.
    Adult length: about 5cm
    Habitat: Surface of leaf litter banks in forest streams.
    Abundance: Common but never very abundant.
    Food: Probably herbivorous.
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    Pyrrhulina laeta
    Pyrrhulina laeta

    Copella nattereri
    Identification: A typical member of the Lebiasinidae - small apical mouth, no adipose fin and a dark horizontal line through the eye. This species is immediately distinguished by the red and black dots along the sides and the distinct red, white and black 'eye-mark' on the dorsal fin. The dorsal fin is used to signal as in aquaria it is sometimes rapidly raised and lowered.
    Adult length: 3-4 cm.
    Habitat: Surface of leaf-litter banks.
    Abundance: Common, reaching densities of 2.76 individuals per sq. m. of leaf-litter surface.
    Food: Small insects and crustaceans.
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    Living Copella nattereri caught in a blackwater stream near Manaus
    Living Copella nattereri caught in a blackwater stream near Manaus

    Preserved Copella nattereri caught in a blackwater stream near Manaus
    Preserved Copella nattereri caught in a blackwater stream near Manaus

    Living Copella nattereri caught in a blackwater stream near Manaus
    Living Copella nattereri caught in a blackwater stream near Manaus

    Nannobrycon eques Steindacher: Brown-Tailed Pencilfish
    Identification: Easily recognized from the other pencilfish in the Tarumã-Mirim by the structure and colour of the tail.
    Colour: In life - yellow background with brown stripes, the lower part of the tail is dark brown.
    Habitat: Hangs in open water above litter-banks or other sheltered areas.
    Abundance: Common, but never found in high numbers.
    Food: Unknown.
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    Lateral view of a preserved specimen of Nannobrycon eques
    Lateral view of a preserved specimen of Nannobrycon eques

    Nannobrycon unifasciatus Steindacher: One-Lined Pencilfish
    Identification: A typical pencil fish, easily recognized from the other pencilfish in the Tarumã-Mirim by the single dark horizontal line running the full length of the body.
    Colour: In life - yellow background with black line. Preserved - gray background with black line.
    Habitat: Hangs in open water above litter-banks or other sheltered areas.
    Abundance: Common, but never found in high numbers.
    Food: Unknown.
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    Lateral view of a preserved specimen of Nannobrycon unifasciatus
    Lateral view of a preserved specimen of Nannobrycon unifasciatus