(Müller & Troschel, 1848)
he first month
of 2016 and we make a return to the Callichthyidae family 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 picta known then as
Hoplosternum thoracatum (now
Megalechis thoracata) was once, 20 or 30 years
ago, held in the same esteem as the fancy L-numbers of today's
picta = male
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 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. The Megalechis
genera has had a checkered history as 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 was a second paper on the genus Megalechis
(1997) 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 M. picta possessing
a band and M. thoracata having a spotted caudal fin.
M. picta also has bands on the body whereas M. thoracata
is spotted. There is quite a marked difference between juveniles
and adults and some juveniles (as seen in image) are quite attractive.
M. personata is now a synonym of M. thoracata.
Megalechis thoracata can be further
distinguished from M. picta by the smaller dorsal-fin
spine, generally higher number of anal-fin rays (six, rarely five
vs. five, rarely four) and mainly by the colour pattern of caudal
fin (see Reis et al. 2005). In M. thoracata the base
of caudal fin displays a whitish band and the remaining part is
dusky or black spotted, while M. picta presents caudal-fin
base blackened, with a conspicuous dark bar in the middle and
the distal border also blackened, the regions between the blackened
bands are clearly whitish yellow.
picta = male pectoral spine
picta = juvenile
To finalise these two species, the paper by P-Y Le Bail and JHA
Mol (2005), discovered after re-examination the holotypes of Callichthys
thoracatus and Callichthys longifilis, which were
used to describe the species now placed in Megalechis.
The fish were found to be those currently known as Megalechis
personata, the so-called Tail-bar hoplo. However, since C.
thoracatus was described first, it had priority and is a
senior synonym. This meant that the scientists needed a new name
for the current Megalechis thoracata, and the next available
name was Callichthys pictus, making the new name for
the fish Megalechis picta.
The above image of
Megalechis thoracata showing you the difference between
the two species.
Megalechis picta is native from
Amazon and Orinoco river basins, as well as coastal rivers of
the Guianas and northern Brazil, it has also been found in the
upper Rio Paraná basin.
Dorsal: 1/8: Anal: 1/5: 25-26 bony scutes
in the upper lateral series, 23-24 in the lower.
Caudal-fin base blackened, with a conspicuous
dark bar in the middle and the distal border also blackened, the
regions between the blackened bands are clearly whitish yellow.
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
7inchs 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.
Keeping this species
is not too difficult a task. (see below)
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.
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.
Sterba's Freshwater Fishes of the
World vol 1.
Dorsal fin: The
primary rayed fin(s) on top of the body.
The median, unpaired, ventrally located
fin that lies behind the anus, usually on the posterior
half of the fish.
Scutes: Bony covering.
megas, megalos = great + greek, echis, -eos = viper
Reis, RE, P-Y Le Bail & JHA Mol, 2005. (New
Arrangement in the Synonymy of Megalechis Reis, 1997 (Siluriformes:
Callichthyidae). Copeia 2005: 678–682.)
Tencatt, Luiz Fernando Caserta; da
Graça, Weferson Júnio and Pavanelli, Carla Simone.
2013. First record of Megalechis picta (Müller and Troschel,
1849) (Siluriformes: Callichthyidae) in the upper Rio Paraná
1997; New Arrangement in the Synonymy of Megalechis (Siluriformes:
Callichthyidae). Copeia 2005: 678-682.