December - Hill Country Cichlid Club

19
Spawning Corydoras Axelrodi….Sort Of! - Keith Arnold
Over a decade ago, I purchased two groups of corys.
One was sold to me as Corydoras axelrodi, while
the second group was sold as C. “deckeri”. I later
learned that “deckeri” is a nomen nudum used for
loxozonus. [The term, nomen nudum, refers to a
scientific name which has never been formally described,
hence has no standing]. I could not distinguish
between the two groups, so I wrote to a wellknown
catfish expert for his input: he never replied.
Since I couldn’t tell the two groups apart, I decided
they were the same species and placed them in a 10-
gallon tank, where they have been ever since.
According to David Sands (1983. Catfishes of the
World, Vol. 1, p. 88a. Dunure Enterprises, Dunure,
Scotland) C. axelrodi lacks the lateral body coloration
of C. loxozons. However, Burgess (1992. Colored
Atlas of Miniature Catfish. T.F.H. Publications,
Inc., Neptune, New Jersey) notes that C. loxozons
has an anterior dark bar on the dorsal fin which
joins the strong lateral line; the latter runs onto the
lower portion of the caudal fin. C. axelrodi lacks
both of these characters as do my fish. Both species
come from the Meta district of Colombia. Sands
(op. cit) cites Rio Meta as the origin of C. axelrodi,
and the Rio Ariari, a tributary of the Rio Guaviare,
as the source of C. loxozonus. It may be that both
occur in the same river drainages, thus leading to
the high similarity in color pattern or the two species
may have evolved from the same ancestor in
which different populations were “captured” with
separation of river drainages. Sands (1984. Supplement
1, p.48b) lists 20 species of Corydoras which
have either a mimic or species with a similar color
pattern; mimics usually occur in the same rivers,
those with similar patterns may or may not inhabit
the same river.
Despite heavy water changes, rich foods and strong
aeration, I never saw any spawning activity. In the