Terrific aquarium dwellers without vertebral column: invertebrates
Although the marine aquarium offers a much larger variety of invertebrates, you can still find a lot of beautiful invertebrates in freshwater aquariums. Shrimps, crustaceans, crabs and snails are very popular animals and you can keep many species in small aquariums. The German Animal Protection Act states, for instance, that you only can keep fish in aquariums from 54 liters upwards!
Shrimps are like crustaceans dependent on oxygen in the water because of their gills. Therefore the aquarium water needs to be well aerated by the filter or an air stone. For the filter it is important that a suction opening is no danger for shrimps (or shrimp offspring)! Please give therefore preference to filters with foam in front of the air intake system. Very suitable are: JBL CristalProfi m greenline , JBL ProSilent TekAir .
For the aquarium water it is imperative to check whether any copper content is measurable ( JBL Copper Test Cu ). If you can measure even a trace of copper you MUST use a special water conditioner ( JBL Biotopol C ) since copper is essential for shrimps, but is deadly in measurable amounts. JBL plant fertilisers ( JBL Ferropol , JBL Ferropol 24 etc.) do contain copper, but NEVER in amounts that can be dangerous for invertebrates. They can therefore be used without any worries.
Selection of invertebrates
You will find an outline of the most important invertebrate groups and their demands here:
Snails can become pests or desired gems. Beautiful and fascinating snail species are becoming more and more popular.
The subphylum of the crustaceans with over 50,000 species has more species than the order of the fish!
One of the most popular animals among aquarium enthusiasts must be the shrimp, since they are peaceful and generally remain small. Shrimps are particularly ideal for enthusiasts with aquariums of less than 50 litres volume.
Many crab species are also very popular. Only a few of them are real aquarium dwellers, however. They prefer an aqua-terrarium with land part to a pure aquarium, filled with water!
Another group are the crayfish, which due to their appearance are also referred to as freshwater lobsters. You do need to know exactly how big the species will grow, since a lot of them can grow to be very large, are incompatible and can also be dangerous for your fish stock.
Dwarf shrimps (Caridina and Neocaridina species) are very sociable animals, whereas longarm shrimps are loners. Larger fish sometimes prey on the smaller dwarf shrimps – while longarm shrimps can prey on fish.
Small crustaceans, such as Gambarellus and Procambarus are peaceful creatures and can be well socialised.
The large Cherax species can be dangerous for other fellow occupants and should ideally be kept in a single-species aquarium. Even if the crayfish leave the fish alone during the day, they may prey on the sleeping fish.
In many crayfish defining the gender is not difficult: the gonopores (genital openings) might look similar, but they are located in different places: on the male they are situated between the rear leg pairs, on the females they are further forward.