Moenkhausia cosmops - Aqualog

Aqualognews NUMBER 96 13
B
esides not looking like a typical
aquarium characin, this species is also
unusual – along with the other 15 members of
its family,the Erythrinidae,known widely as the
trahiras – in lacking the characteristic adipose
fin borne by the vast majority of its cousins.
But,to me,perhaps the most striking feature is
not morphological. Rather, it’s the extreme
slipperiness of these medium-sized predators.
I remember vividly collecting a close relative of
E.erythrinus – the aimara or jejú (Hoplerythrinus
unitaeniatus) – in a backwater or the Rio Negro,
and not being able to hold on to it for any
length of time. This was not only because of
the impressive power packed into the muscles
of the creature, but because of the extremely
slippery nature of its thick covering of body
mucus. Indeed, I immediately nicknamed the
specimen,the ‘soap fish’!
CRITTERS
Erythrinus erythrinus -
the Red Wolf Fish
by John Dawes
It looks nothing like a cardinal tetra or any of its numerous colourful,
small, shoaling relatives, but Erythrinus erythrinus is, nonetheless, a
characiform, i.e. member of the order characiformes, just like them.
This small family of trahiras is divided,at least,at
the moment, into just three genera: Erythrinus
(two species), Hoplerythrinus (three species)
and Hoplias (11 species). Of these, perhaps the
Erythrinus sp. “Peru” is very attractively colored. Photos: Frank Schäfer