NEWS107
43
n the at least 100million years of their
existence the evolutionof characins in
SouthAmericahas followedamultitudeof
paths.Someof thebest-known fishspecies
of SouthAmericabelong to the characins,
for example Neon Tetras (
Paracheirodon
)
andpiranhas (
Pygocentrus
).Numerousnew
species continue to be discovered every
year. In recentweeksAquariumGlaser has
beenable tomakeanumberof interesting
and beautiful species available to the
aquariumhobby.
Crenuchus
sp."Venezuela"and
Crenuchus
cf.
spilurus
"Venezuela"
Crenuchus spilurus
iswidelydistributed in
South America. Or so it says in the text-
books.But is that really true? Ifwe look so-
mewhat closer thenwewill find that the
Crenuchus
from Brazil, Peru, Guyana, and
Venezuela differ considerably from one
another. But at present only a single spe-
cies is scientificallydescribed,namelyCre-
nuchusspilurus,whichwasdescribed from
the EssequiboRiver inGuyana byA.Gün-
ther in 1863. From this it canbe assumed
thata revisionof thegenuswould result in
several new species having to be descri-
bed.
Crenuchus
areverynoteworthy fishes.The
malesgrowsignificantly larger than the fe-
malesanddevelopgreatlyenlargeddorsal
and anal fins that canbe spread like sails
duringcourtshiporwhenmalesdisplay to
eachother.And then these fishes look re-
allysplendid.Thedorsal fin in females isal-
ways unpatterned, and evenpoorly deve-
lopedmales canbe readily distinguished
I
Crenuchus
sp.Venezuela,male
Photos:FrankSchäfer
There are characins inbothAfrica and SouthAmerica.This demonstrates
that theyevolvedata timewhen the two landmasseswerestillpartof the
sameprimeval continent known as Gondwanaland. SouthAmerica sepa-
rated fromAfricaaround100millionyears ago.Toput that inperspective:
themassextinctionof thedinosaursbeganaround60millionyearsago.
Newcharacins from
SouthAmerica
byFrankSchäfer
from femalesby this feature.Thespecies is
commonlyknownas theSailfinTetra in the
aquariumhobby.
Unfortunately only very little is know
about the lifeof
Crenuchus
in thewild.They
probably livebypreference insmallblack-
waterstreamswithabundant leaf litter.Be-
causemales establish anorder of rank in
theaquarium it canbeassumed that they
also live incolonies in thewild.But theyare
far frombeing shoaling fishes. Everymale
possessesapotentialbrooding territory,an
essential feature of which is thepresence
of a cave-like retreat.This iswhere spaw-
ning takes place and themale then assu-
mes the duty of caring for the eggs until
theyounghatch.
Crenuchus
can be maintained either in
largenumbers in largeaquariawithacon-
long, they are not very active swimmers
andusuallymove only a few centimeters
from thebreeding cave.
Crenuchus
canbe
fedalmost all theusual typesof food (dry,
live, frozen) in the aquarium, although ve-
getable food is refused.
AquariumGlaser has been able to import
two species of
Crenuchus
fromVenezuela
that areclearlydifferent incoloration.One
of these species looks like
C. spilurus
and
has the distinct caudal-peduncle spot so
Currentnew imports
Crenuchus
sp.Venezuela, female
Crenuchus
cf.
spilurus
Venezuela, female
siderable amount of cover, or inpairs.The
latter form of maintenance often takes
place inverysmallaquaria,asalthoughCre-
nuchus males can grow to a good 6 cm
