Crystal rainbow tetra named Trochilocharax ornatus


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German ichthyologist Axel Zarske has described a new genus and species of transparent tetra from Peru.

Naming the new tetra Trochilocharax ornatus in a recent issue of the journal Vertebrate Zoology, Zarske distinguishes the new tetra by its naked, scaleless (transparent in life) body (although males have a single pouch scale at the base of the caudal fin). 

Other features useful for distinguishing the new tetra are the presence of 2 unbranched and seven branched dorsal-fin rays, the presence of four unbranched and 22–24 branched anal-fin rays, and one relatively large hook on seven (fourth to tenth) anal-fin rays. 

The presence of five to eight conical teeth on the narrow upper jawbone, upper and lower jaws with irregularly distributed conical teeth that partly protrude out of the mouth, and 34–35 vertebrae also distinguish this species.

Trochilocharax ornatus has been exported for the aquarium trade since 2003 (where it has been misidentified as a species of Heterocharax or Tyttocharax). 

This tetra has been given the common name of "crystal rainbow tetra" in the aquarium trade; in Germany, it is known as the Kolibrisalmler (=hummingbird tetra).

The exact distribution of the new tetra is not clear.  According to the author, some sources cite the blackwater streams of the Ampiyacu River drainage, while others consider the Nanay River drainage to be its true distribution.

The genus name combines the hummingbird family Trochilidae and –charax, meaning stake, in reference to the dentition; the species name is Latin for an embellishment or decoration, in reference to its striking live colour.

Trochilocharax ornatus is an internally inseminating species of tetra, like members of the characid subfamilies Glandulocaudinae and Stevardiinae (to which it belongs).

For more information, see the paper: Zarske, A (2010) Der Kolibrisalmler – Trochilocharax ornatus gen. et spec. nov. – ein neuer Salmler aus Peru (Teleostei: Characiformes: Characidae). Vertebrate Zoology 60, pp. 75–98.