(Valenciennes in Cuvier & Valenciennes
his month we once again return to the family
Callichthyidae but this time not to your ubiquitous Corydoras
but to an old friend in the eyes of the aquarist of the more advancing
years and a reminder that Megalechis thoracata was once,
20 or 30 years ago, held in the same esteem as the fancy L-numbers
of today's 21st century.
In the 1960's and 70's the catfish
that the average U.K. aquarist could only get a hold of were the
Corydoras with aeneus and paleatus being
the norm with maybe a few other varieties thrown in. Only a few
specialist shops were bringing in the more unusual pets such as
a few Synodontis when imports from Africa were obtainable
and the more common plecs such as the different varieties of whiptails
from South America. That is why the "port" or "spotted
hoplo" alongside Callichthys callichthys were much
sought after all these years ago.
You can distinguish between our factsheet of the month and Callichthys
callichthys by the shape of the caudal fin with the latter
being more rounded and also possessing smaller eyes.
You may be more used to the name of Hoplosternum thoracatum
when this fish was more popular but this genus was revised
in 1996 by the Brazilian Ichthyologist, Roberto E.Reis, and only
Hoplosternum littorale was kept with him creating a new genus
for thoracata with a second species added, Megalechis
personata. There has now been a second paper on the genus Megalechis
(1995) and what we used to know as M. thoracata is now
M. picta. The difference between these two species rests
on the pattern in the caudal fin with picta possessing
a band and thoracata having a spotted caudal fin. M.
picta also has bands on the body wheraes thoracata
To differentiate between the sexes is not too hard. The males
posses thicker pectoral spines with minute hairs adorning them
and have an orangey colouration when in breeding condition (see
top picture) If you can see underneath your specimens you will
also see that the female has a broader gap between the thorax
plates than the male so as to give room to the swelling which
is involved when carrying eggs.
Dorsal: 1/8: Anal: 1/6-8: 25-26 bony scutes
in the upper lateral series, 23-24 in the lower.
Dark olive-brown to grey-brown. Upperside
often blackish-olive, underside pale brown to whitish. The whole
body including the belly, is covered with large and small black
blotches. Fins are spotted. Caudal fin with a spotted pattern.
Keeping this species is not too hard. They
can become quite boisterous in a community setup with their digging
and unsettling other fish at night but as long as your other inhabitants
are of a decent size and are not "Neon Tetra size", as
remember this fish can get to nearly 8inchs in size and a small
1 inch tetra at night may be too much of a temptation to even the
most docile of animals. The only time they can get aggressive is
if you have a pair and they are in the throes of spawning as the
males can get quite tetchy and it is not unknown for a male to kill
the female in the quest to produce a family. This does not happen
all the time but best to keep a look-out for any aggressive behavior.
This species is a bubblenester with the male
building it at the water surface. The female lays her eggs in the
nest and the male looks after them. This is the point that you may
have to take the female out of the tank as the male may kill it,
as they can get aggressive when guarding the nest.
A good quality flake and tablet food. They
also relish garden worms and frozen bloodworm.
Sterba's Freshwater Fishes of the
World vol 1.
Reis, RE, P-Y Le Bail & JHA Mol, 2005. (New
Arrangement in the Synonymy of Megalechis Reis, 1997
(Siluriformes: Callichthyidae). Copeia 2005: 678–682.)
Top: Chris Ralph
Left: Julian Dignall @
Right: Allan James @
exaratus, C. personatus, Hoplosternum personatus, H. thoracatum
surinamensis, Megalechis personata
America: Amazon and Orinoco River basins, as well as
coastal rivers of the Guianas and northern Brazil.
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