fixed to the last body segment of the larvae and goes through the
egg shell to the swimmerets of the berried (egg-laden) female. No
other representative of the crustaceans has developed a comparable
There is one all-important aspect of keeping crayfish that goes
Crayfish Tank Setup
far beyond the aquarium hobby and needs to be brought to the
general public’s attention. As global trade with these invertebrates
is booming, they have started to become an increasing danger
for the environment: Should crayfish be released into nature by
irresponsible aquarists, they pose a grave danger for the native
crayfish population and other aquatic organisms. The entire biotope
may be seriously compromised.
When the volume is the same, an aquarium with a larger
footprint is always preferable, since water depth is not as important
for crayfish as the usable surface, which is what dictates how many
crayfish you can keep in a tank. Depending on the size and the
aggressiveness of a species, tank décor is also a very important
factor. Crayfish need structure, horizontal as well as vertical, and a
sufficient number of places to hide.
Moreover, they are true escape artists, and they will use every
tube, hose, and cable leading out of the tank to have a closer look
at their surroundings—which, unfortunately, often ends in their
death. Even a tad of silicone jutting out at the corner of the tank
can serve as a way to escape the aquarium. Thus, a tank cover is not
only absolutely necessary, but it also needs to be very tight. Make
sure you close off every cable feedthrough with foam or netting. If
your crayfish are of a larger species, keep in mind that they have
enormous strength and can lift tank covers seemingly without effort
if they are set on leaving the aquarium.
The majority of crayfish need a cave for their well-being. Some
species also take cover in dense vegetation and only build tunnels
when their aquatic habitat threatens to become dry, so they need a
moist, well-protected retreat.
As it is hardly possible to have a loamy
stable ground in the aquarium for the crayfish
to burrow into, we need to provide them with
other materials that they can use to build their
caves. A slab on a sufficiently thick layer of
sand and gravel propped up by smaller rocks
is the simplest option. The crays can dig
out the gravel below and create a tunnel for
Driftwood, coconut shells, clay flowerpots,
and clay tubes are suitable hiding places, too.
There are hardly any limits for a designer’s
imagination. The important thing is that each
crayfish can build and live in its own cave. It
is even better if the number of hiding places
exceeds the number of crayfish so they can
Many crayfish species are nocturnal or
crepuscular, which makes lighting somewhat
less important outside the aesthetic
considerations. A strong filter is great in a
crayfish tank. Crayfish break down their food
into very small parts when eating, whether
they have tablet food or a piece of fish, and
small particle clouds tend to spread and spoil the water.
Some crayfish species may be socialized with small fish or dwarf
shrimp with identical requirements regarding the water parameters.
These fellow occupants soon learn how to make use of these
additional sources of food and take care of a large part of these food
particles, which would otherwise go to waste.
Their requirements regarding water quality differ from species to
species, though crayfish generally tolerate a rather large range of
water parameters. The great robustness and adaptability of some
C. pekyni “blue Kong.”
Blue claw zebra crayfish (Cherax peknyi), from West Papua and
Papua New Guinea.