thoracata(Valenciennes in Cuvier
& Valenciennes , 1840)
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
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
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
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.
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
whereas M.thoracata is spotted.
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.
exaratus, C. personatus, Hoplosternum personatus,
H. thoracatum surinamensis, Megalechis personata
and Orinoco River basins, as well as coastal rivers
of the Guianas and northern Brazil.
Dorsal: 1/8: Anal: 1/6-8: 25-26
bony scutes in the upper lateral series, 23-24 in
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.
Care & Compatibility
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.
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
A good quality flake and tablet
food. They also relish garden worms and frozen bloodworm.
The median, unpaired, ventrally
located fin that lies behind the anus, usually on
the posterior half of the fish. Caudal fin:
The tail. Dorsal fin: The primary rayed fin(s)
on top of the body. Scutes:
RE, P-Y Le Bail & JHA Mol, 2005. (New
Arrangement in the Synonymy of Megalechis Reis,
1997 (Siluriformes: Callichthyidae). Copeia 2005:
Gunther;Sterba's Freshwater Fishes
of the World vol 1.