NEWS103
20
Since1stAugust2014newanimalprotection legislationhasbeen in force in
Germany,underwhich thevendor isobliged toprovideeverynewcustomer
withextensivewritten in informationon thenewlypurchasedanimal. In the
caseof fishes that is totally impracticable forevery individual species.For this
reasonAQUALOGhasdeveloped "Profile" sheets tocomplement its ”Labels”
system, in order to comply with the legal requirements and cover each
individual fish group. Labels and Profiles are an unbeatable "dream team".
Here is theProfile for "Characins".
Characins
byFrankSchäfer
Labels
General
Characins is the termused forawholesetof
fish families fromAfrica and SouthAmerica
that have certain anatomical features in
common, but can be very different in
appearance. The characins include, for
example,notonlythetinyNeonTetraand its
close relatives (
Paracheirodon
), but also the
piranhas (
Pygocentrus
) and the African
tigerfishes (
Hydrocynus
),which cangrow to
more thanameter long.
Because of the vast variety of species only
thesmallcolorfulcharacins-thosethatdon't
normallyexceedaneventual sizeof 10cm -
will be discussed here.The piranhaswill be
covered in a Profile of their own, and the
other large species are so rare and so
expensive in the trade that they are
maintainedonly by experienced specialists,
zoological gardens, and the like, who have
access to relevantspecialist literature.
From a zoological viewpoint the following
test dealswithmembers of theCharacidae,
Crenuchidae,
Gasteropelecidae,
and
Lebiasinidae fromSouthAmerica, aswell as
the Alestidae and Distichodontidae from
Africa.
Importantrequirements
Characins are popularly termed "shoaling
fishes", which is, strictly speaking, only very
marginally correct. They are in fact social
fishes that sometimes join together to form
larger groups, but often also occupy very
small territories that are even defended
againstconspecificsonashort-termbasis.In
practice thismeans thatcharacinsshouldbe
kept ingroupsof sixormore individuals,the
upper limit being determined only by the
sizeof theaquarium.
A largenumber of the species of interest to
theaquariumhobbyhaveadaptedtowaters
that are inhospitable to other, larger fishes,
specifically small bodies of water with soft
acidwater.Thechemical compositionof the
water is, however, of no physiological
significancetocharacins;aCardinalTetracan
live just as long in medium-hard, slightly
alkaline water as a conspecific kept under
near-natural water conditions. Very good
water quality, inparticular as demonstrated
by thedensityof thebacterial population in
the water, is of far more importance. The
majority of characins maintained in the
aquarium require well-maintained water
witha lowgermcount.Thiscanbeachieved
viaefficientbiological filtration, theaddition
ofhumicsubstancesusingpeat,Aldercones,
ordead leaves (therearealso suitable liquid
preparations available), the best plant
growth possible (many aquatic plants
produce antibiotic substances that have a
limiting effect on bacterial growth), and
regular partialwater changes,which should
beasextensiveaspossible (seebelow).
Theappropriatewatertemperature for long-
termmaintenance is generally between 22
and 26 °C, but almost all characins can also
survive temperaturesofup to30 °C forshort
periods (a fewdays toweeks) andalmost all
specieswill tolerateashort-termdrop (a few
TheCardinal Tetra (
Paracheirodonaxelrodi
), familyCharacidae, isnot onlya characinbut alsoone the
most important of all ornamental fishes.
MarbledHatchetfish,
Carnegiellastrigata
,from
the familyGasteropelecidae.
The
Congo
Tetra,
Phenacogrammus
interruptus,
is thebest-knownmember of the
African characin familyAlestidae.
