Invertebrates and amphibians

Though it has long been the practice to have invertebrates in a freshwater aquarium, a more targeted approach has been adopted in recent years.

Tower-cap and post-horn snails have been found for quite some time in aquariums. In particular, the burrowing tower worm basically aerates the soil and utilizes organic plant compounds. Although they thus ensure healthy plant growth, they were always in aquariums more as just animals.

The trade also offers increasingly noticeable colored or shaped snails, such as the different types of apple snails or the Neritina natalensis. Because of their high metabolism, they must be included in the maximum number of animals the aquarium will endure. The minimum edge length for an apple snail is 60 cm.

For some years, there has also been an increase in the number of shrimp kept in freshwater aquariums. Their popularity is due mainly to the Japanese aquarist and photographer, Takashi Amano, who started keeping Caridina shrimp in his aquarium for algae control. This has led to an increased introduction of other shrimp species.

Offered in trade as well are certain crayfish. In the freshwater aquarium, it is mainly crayfish species belonging to the fauna of Australia or North America. These are similar in their habits to lobster crayfish and are grown mostly on farms for food purposes.

In the pet trade there are mainly blue-colored pieces such as the yabbies, the marron and red claw lobster. All three types require very large aquariums, and can be associated only with large fish; they also lay hands on the aquarium plants. Tiny orange dwarf crayfish are also popular.

Amphibious crabs, however, are rarely maintained in the aquarium. For their well-being they always need a sufficiently large rural area and are therefore better off in a vivarium.

Amphibians are rare wards in the aquarium. The species maintainable in the aquarium are clawed frogs, dwarf frogs, the Japanese fire belly newt, the axolotl and the Typhlonectes.