Are crabs suitable for community tanks?
In general, crabs should be better kept in a species aquarium. Many crustaceans eat fish or plants, for example. Smaller crustaceans, on the other hand, are threatened by larger fish.
General information about crabs
All crabs have 10 feet. That is why it is sometimes referred to as decapod crabs.
Basic problems when keeping crayfish:
- Crabs usually move quite slowly
- Crayfish have many sensitive body parts, feelers, eyes etc., and are therefore vulnerable to ‘nibble’ fish
- Many crabs have powerful claws
- Crayfish sometimes eat plants or are not particularly careful with plants
- Crayfish can climb out of the aquarium
At least when socializing with fish that live or sleep on the bottom, you have to be careful. Crayfish don’t necessarily hunt fish directly, but if they get a fish between their claws at night, they’ll snap. Crayfish have very poor eyesight. You smell and feel all the better for it.
marble crabs for example, even snail cichlids of the species Neolamprologus ocellatus can pull out of their snail shells at night. Even if the fish are about 2/3 the size of the crabs.
Plants are not eaten by all crustaceans, but many species at least pluck plants from the ground. However, some species simply climb over plants.
Crabs shed their skin because the shell cannot grow with them. Juveniles molt more frequently. Adult crabs molt regularly every 4 to 6 months. A few days before a moult, little or nothing is eaten. After moulting, the crabs are very soft and are readily eaten by fish. That is why freshly skinned crabs hide very well for up to a week.
To build up their shells, crabs seem to prefer calcium-rich food, i.e. anything with chitin such as mosquito larvae, mysis, etc. In principle, however, they are omnivores. Corresponding to the need for lime, very soft water seems to slow down or limit growth.
Crayfish need to be taken care of very well so that the next tank can grow well. Otherwise these animals can die during the molting.
Lousiana dwarf crabs, Cambarellus schriffeltii, are peaceful but only about 3 centimeters long. These crabs are in turn endangered by larger fish.
Next to the marble crabs the Cuban crayfish, Procambarus cubensis, is probably the most suitable for a community aquarium.