Catfish of the Month Right Arrow March 2009 • Article © Julian Dignall, uploaded March 08, 2009

Hi Fin Peppered Cory, Bigfin Cory, Sailfin Cory - Scleromystax macropterus   Regan, 1913

An uncommon find that I kept a few years ago now is Scleromystax macropterus, the species name meaning long finned — and then some - and it was this feature that made the fish initially appealing to me. Adult males of this species are readily identified because the dorsal and especially pectoral fins are elongated up to five times their normal size — to the point the fish look very ungainly indeed. This development isn't a given, it may not occur and it is most obvious on the dominant male of a group. To my mind it reminds me of antler development in stags. That these long fin rays are similarly deployed amongst competitive males may be taking this speculative observation too far however.

Keep an eye out for this fish though, it's quite possible with the shift in export patterns out of Brazil of late, that the exporters will turn their attentions to the Atlantic coast drainages of Sao Paulo state and south. Furthermore, Scleromystax macropterus is found to live alongside S. barbatus in some of its range, here we find it in sub tropical climes, yet still in blackwater. Here it rarely will encounter aquatic plants, but rather finds refuge in shady overhanging or partially submerged vegetation at the side of wood and leaf strewn streams with water the colour of tea. It's reported in the wild it prefers a higher vantage point in the water column than S. barbatus.

In the aquarium then, it's important to keep this fish under pH 7 and relatively cool. It's also important to give them more space than perhaps you would afford a typical Corydoras group, dominant males are surprisingly aggressive. Perhaps this in part explains why this species has not yet bred in captivity. I think also the unusual set-up (from the point of view of comparison with a typical Corydoras breeding set-up) it would require soft, acidic water, kept cool, power filtration and possibly floating plants (to replicated submerged vegetation), perhaps optionally leaf litter and good lighting to penetrate the tea coloured water. Put altogether, that's not what most Corydoras breeders have in their average tank although breeding successes with other Scleromystax suggest it's maybe just a matter of dedicating some time to such a project.

Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

Jump to next section Cat-eLog Data Sheet
Scientific NameScleromystax macropterus  Regan, 1913
Common NamesHi Fin Peppered Cory
Bigfin Cory, Sailfin Cory
Type LocalityBrazil, Paraná, Paranaguá (25°32'S, 48°36'W)
Synonym(s)Corydoras macropterus
Pronunciationss KLER oh muss tax - mah CROPP terr uss
EtymologyScleromystax: From the Greek sclero meaning hard and the Latin mystax meaning moustache. This specific epithet refers to its long (makros=long) feather-like fins (pteron=feather, fin).
Jump to next section Species Information
Size 100mm or 3.9" SL. Find near, nearer or same sized spp.
IdentificationA reasonably easy species to ID when adult due to the finnage. Generally more elongate than similarly patterned species. Females may be confused with other species.
SexingThis species' males have (very obvious) longer pectoral and dorsal fins.
Jump to next section Habitat Information
DistributionCoastal rivers from São Paulo to Santa Catarina, Brazil and some upper Paraná River tributaries.
Santa Catarina State Rivers (click on these areas to find other species found there)
La Plata, Paraná, Upper Paraná (click on these areas to find other species found there)
Sao Paulo State Rivers (click on these areas to find other species found there)
Show it on a map (Click the map-icon to show/hide map of species distribution)
pH5.4 - 7.0
Temperature16.0-20.0°C or 60.8-68°F (Show species within this range)
Other ParametersRequires cooler water but can be kept reasonably warm if water is well aerated - this is not recommended for long periods of time. Tolerant of high pH if acclimated gradually.
Jump to next section Husbandry Information
FurnitureSmooth pebbles and sand with bogwood and dried beech or oak leaves to leech tannins into the water. Plants can be used but are not necessary.
CompatibilityPeaceful community tank inhabitant although it's water requirements (cool blackwater) tend to limit selection somewhat. If the aim is not reproduction then these fish will tolerate higher pH closer but still below neutral. Mature males will fight often inflicting significant damage, keep in a large area or overcrowd them to avoid this. Ratios of males to females does not seem to avert this behaviour. Overcrowded small tanks will require meticulous water management.
Jump to next section Further Information
ReferencesAnnals and Magazine of Natural History (Series 8) v. 11 (no. 62).
Registered Keepers(1) Coryologist (k: 5), (2) smegforbrains, (3) ayrtoninst (k: 15), (4) mike h, (5) This Old Spouse, (6) archaquatics, (7) kjeanb, (8) Baked Wafl3, (9) Nabobmob1 (k: 5), (10) rmc, (11) Mexnotex.

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Breeding ReportsNone.
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Last Update2013 Jul 15 13:17 (species record created: 2009 Mar 08 06:28)

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