NEWS102
41
Bloodworm
Water flea
Tubifex
Glassworms are an outstanding live food.
It is important to note that these larvae
are little predators and hence, for safety’s
sake, they shouldnot be fed to any fishes
with a total length of less than 2 cm.
Larger fishes are never attacked or
harmed inanyotherwaybyglassworms.
Glassworms are a perfect food for
bringing barbs, characins, labyrinthfishes,
and cichlids into spawning condition.
2.“Jumbo”bloodworms
The
midges
that
develop
from
bloodworms–chironomidmidges (family
Chironomidae) – are likewise no threat of
any kind to humans, as again these
midgesdon’t biteanddon’t suckblood.
The chironomidmidges are very species-
rich, with more than 5,000 species
worldwide and more than 570 species
known in Germany. In the wild these
midge larvae constitute one of the most
important sources of food for wild fishes.
Because
chironomid
larvae
are
ecologically very adaptable, there is
virtuallynoaquaticenvironment inwhich
they do not occur. They are absent only
from the open sea, but there are species
thatmake their living in tidal pools.
The large “Jumbo”bloodworms represent
an excellent treat for larger fishes
(upwards of around 5 cm total length).
They feedondeadplant particles (mulm)
andbacteria, so they represent nodanger
of anykind toaquarium livestock.
Bloodworms aren’t free-swimming like
glassworms, but live on and in the
substrate,where they construct a type of
tube to live in.For this reasonbloodworms
are also a particularly good food for
bottom-dwelling fishes.
The deep red body color and the jerky
mode of swimming of bloodworms are
extremelyattractive to fishes.Hence these
midge larvaearealsoparticularlygood for
pampering fishes that arepoor feeders.
Their filter-feedingbehavior alsomakes it
possible to enrich them with water-
soluble medications that need to be got
into the fishes in order to be effective (in
the event of intestinal parasites, for
example). In short, bloodworms are an
ideal fish food.
3.Water fleas
Water fleas (family Daphniidae) are not
actually fleasatall.Fleasare insectsand liveby
feedingonbloodwhenadult.Water fleas are
crustaceansandfeedthroughouttheir livesby
filtering micro-organisms from the water.
Hence even the fussiest person in the
household need have no concerns about
these foodorganisms.
Waterfleasarepartofthefreshwaterplankton
and live in standing or slow-flowing waters.
They are filter-feeders that feed on micro-
algae, bacteria, etc. They are very interesting
creatures biologically. For themajority of the
year they produce live young via
parthenogenesis (ievirginbirth).Theseyoung
aregeneticallycompletely identicalwith their
mother,ieso-calledclones.Onlywhenthedays
become shorter, or the water in which the
water fleas live threatens todryup,domales
appear. These originate from fertilized eggs
andnow in their turn inseminate the females,
who immediatelyproduce rather largewinter
eggs. These eggs are very resistant and can
even tolerate completely drying-up of the
wateror freezing.Becausetheseeggsarevery
light,theycanalsobeblownby thewind,and
in this way water fleas sometimes colonize
even tinybodiesofwater suchaspuddles in
country lanesandpaths,etc.
Water fleas are particularly suitable as food
organisms as their jerky, hopping mode of
swimming is very good at getting the
attention of fishes. The nutritional value of
water fleas is rather small, but they are
neverthelessan important food,asontheone
hand they are very rich in roughage, andon
the other they provide predominantly
carnivorous fish species with their greens.
Because, as already mentioned, water fleas
filtermicro-algaefromthewater,theirgutsare
always full of thisvitamin-rich supplementary
food.
Water fleas are very sensitive to toxins in the
water. In the past the “water flea test”was a
recognizedmethod intoxicology(thestudyof
poisons).Sowater fleas arealsovery suitable
for testingwhether anaquarium that has, for
example, been treated with an “aggressive”
medication,canbe repopulatedwithdelicate
fishes orwhether residues of themedication
arestillpresent.
4.
Tubifex
Fora longtime
Tubifex
wastheonly live food
that was always available in the pet trade.
Tubifex
or tubificidworms (familyNaididae)
areannelidworms,and thusdistant relatives
of the earthworms.
Tubifex
live in the
substrate of bodies of water, where they
construct tubes from mud and skin
secretions (thename
Tubifex
isderived from
the Latinwords for“tube”and“make”).Here
they feedondead,decayingorganicmatter.
The red color of
Tubifex
worms comes from
haemoglobin, that is, the same blood
pigment that we humans also use to bind
oxygen.Becausehaemoglobinbindsoxygen
veryeffectively,but theoxygen requirement
