Results for “pigment”

This species is traded under various other names including 'red arc pencilfish', 'Peruvian red pencilfish', 'ruby red pencilfish', 'red pencilfish', and Nannostomus cf. marginatus 'red'. It was initially described as a subspecies of N. marginatus but can be identified by the following combination of characters: pronounced sexual dimorphism with adult males exhibiting bright red pigmentation between the central...

In live fish colour pattern is perhaps the most useful way to identify N. rubrocaudatus plus the closely-related N. marginatus and N. mortenthaleri. N. marginatus is immediately distinguished from the other two by the fact it lacks red pigmentation on the body in males, but N. mortenthaleri and N. rubrocaudatus are more easily-confused. Males of N. rubrocaudatus can be told apart fro...

This species is distinguished from similar-looking congeners such as N. longistriatus and N. ornatus by its unique colour pattern consisting of a black lateral body stripe with 9-16 vertically-orientated blotches extending along it both above and below, plus an irregular stripe running along the dorsal surface. The anterior lateral blotch is surrounded by lighter pigment, forming an ocellus similar to that seen in N. binotatus.

This unidentified species has been traded since the mid-00s and appears to be a member of the P. khulii-oblonga species group as per Bohlen et al. (2011). There are two similar-looking forms; one has a darker body, dark pigmentation in the pectoral fins and barbels and a blue sheen on the head, while the...

For aquarists perhaps more useful are the subtle differences in colour pattern with P. simulans differing from both P. innesi and P. axelrodi in possessing a greener (vs. bluer) lateral stripe which covers more (vs. less) of the eye/head and extends to the caudal-fin base (vs. terminating anterior to caudal-fin base), a lesser (vs. greater) amount of relatively duller (vs. brighter) red pigmentation on the flanks. The taxonomic history of all three species is complicated with earlier authors such as Géry (1960, 1977) ten...

Within this assemblage P. manipurensis is most similar to 'P.' meingangbii and P. padamya by virtue of the fact that males in all three possess orange-red pigmentation on the flanks and caudal-fin. It can be told apart most easily by the fact it possesses a relatively small, spot-like humeral marking, vs. a vertically-elongated, relatively large humeral marking in both the other species.

The genus Prionobrama currently contains only one other valid species, P. paraguayensis. It is very similar in appearance to P. filigera, but lacks any red pigmentation in the caudal fin. It's probably never been imported for the hobby, although it may show up as occasional bycatch amongst shipments of more popular species. P. filigera can be easily distinguished from the "other" bloodfin tetra, Aphyocharax anisitsi by its more elongate body shape and the fact that it exhibits...

Following Fink (1993), P. piraya can be distinguished from congeners by the following combination of characters: adipose fin with rays in larger specimens (vs. always without rays in other Pygocentrus species); branched dorsal-fin rays 15-18, usually 16 (vs. 14-18, usually 15); usually 7 neural spines anterior to first pterygiophore (vs. usually 6); vertebrae 36-39, usually 38 (vs. 35-38, usually 36). It can also be identified by colour pattern since it possesses distinctive bright yellow-orange pigmentation on the lower jaw, opercle and lateral body in life.

This species occurs in several colour forms depending on collection locality with some exhibiting more intense pigmentation in the fins or an additional reddish lateral stripe, for example. It's sometimes said to closely resemble and occur sympatrically with Rasbora agilis, but that name is currently considered a junior synonym of the congener Trigonopoma pauciperforatum. R. agilis had previously been us...