Page 19 - lukhaup_pekny_invertebrates

Since the late 1990s, ornamental freshwater
shrimp have been an integral part of the hobby.
Before that turning point, pet stores sold them
from time to time, usually as live food. But then, a
veritable boom set in, and today shrimp may even
be the most popular inverts in our aquaria.
The shrimp common in our hobby belong to
different genera and families, scientifically speak-
ing, but what unites them is that they spend all of
or at least the most part of their lives, especially as longing to one of these groups. Practically every
adults, in fresh water.
Some species have not become entirely inde-
pendent of the original habitat of their ancestors,
the sea, and they need brackish or marine water
for reproduction. These species belong to the so-
called primitive type and produce large numbers
of very small eggs per batch. The larvae hatching
from these eggs are released into the open wa-
ter, where they form part of the plankton and go
through many stages of development. Only to-
wards the end of their time as larvae do they start
a benthic life on the ground. Around this time,
they also migrate back to pure fresh water.
During the course of evolution, freshwater
dwarf shrimp have spread from the estuaries
of larger rivers to rapidly-flowing creeks in the
mountains, to enormous lakes, the smallest trick-
les of water and even to cave waters. They are
found from tropic to temperate climates today,
however, they have not conquered the arctic re-
gions yet. The abundance of different habitats has
resulted in a great variability in shrimp species
and in stunning forms. Their sometimes truly
impressive colours and patterns are the result of
their adaptation to the different living conditions SHRIMP
in their habitats.
From all the different shrimp in the world, only
representatives from three groups have managed
to find their way into our aquaria - dwarf orna-
mental shrimp, fan shrimp and long-arm shrimp.
They differ in body size and form as well as in
their habits. The requirements regarding their en-
vironment do not differ much between shrimp be-
shrimp available in the trade belongs in one of the
three groups, under systematical aspects. Dwarf
shrimp are probably the most prominent and also
the most popular among them. They have found
their way into the aquaria and into the hearts of
their keepers in allmost all the world.
The shrimp offered in the trade today are rather
variable in size. Dwarf shrimp with a total body
length of around 15 mm and long-arm shrimp of
the genus Macrobrachium, some of whose repre-
sentatives can grow to a body size of over 50 cm
in length, of course differ considerably when it
comes to their keeping requirements. For this
reason it is practically impossible to describe
a “typical” shrimp tank – you’ll have to decide
which species or at least group of species you want
to keep. Dwarf ornamental shrimp can be kept in
tanks as small as 20 litres upwards. Smaller tanks
are available in the trade, however, they bring
about some grave disadvantages. The smaller wa-
ter body reacts too fast to temperature changes in
its surroundings, and it is difficult to achieve sta-
ble water parameters in there.
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