
The aquarium and its inhabitants - the fish - constantly enjoy a large fan base. And newcomers are always enthusiastic about the calming world under water. In order to set the right course for successful operation when setting up or changing aquariums, we explain which fish go together and which combinations should be avoided.
Demands of individual fish species
Similar to a garden in which not every plant thrives in every neighborhood, not all fish families and species are suitable for populating one and the same aquarium together. There are several reasons why this is the case.
The water temperature
Just as land animals can live in the tropics, Antarctica or anywhere in between, fish inhabit a wide range of temperature and climate zones. Since the individual fish species cannot simply be acclimated to a different water temperature, the population of the aquarium, i.e. all fish species used, must share the same temperature range.
The water quality
In addition to the water temperature, other parameters also play a role. These can be:
- oxygen content
- PH value
- other parameters (salinity, water hardness, carbonate hardness)
If these parameters in the aquarium do not correspond to the needs of the fish, breathing and circulation can be impaired and the animals can even die.
The aquarium
Relevant issues here are:
- Pool size (water volume)
- Pool layout with water depth and pool length
- Design (planting, ground conditions, hiding places, etc.)
In summary, one could say that each animal has both quantitative and qualitative requirements for its territory. A socialization is particularly possible if the requirements harmonize, or at least do not interfere with each other.
The morphology and habits of fish
Finally, the fish themselves remain. Possible aspects for a possible socialization can be:
- body size and shape
- Swimming behavior (current, bottom fish, etc.)
- Diets (type of feed and food intake)
- General lifestyle (single, pair or school fish)
It is not only interesting whether the fish fit together in terms of possible competition or even hostilities, but also whether the aquarium is suitable for the fish species in question.
Examples of successful socialization
With this knowledge, suitable fish for the socialization in the home aquarium can be determined in the following.
NOTICE: In the following, we assume that the "basic theme" of the design, i.e. size, water parameters, planting, etc., is fixed and should now be filled with suitable life. Of course, you can also go the opposite way and adjust the aquarium according to the fish species you absolutely want.
The space-saving aquarium
Whether as an entry into aquaristics or for limited space, even a small dimension of the tank can be filled with life. For a small water volume from around 60 liters, for example, companies from:
Variant 1 - perch and platys
Individual fish as eye-catchers:
- parrot platy
- Red platy
- butterfly cichlids
ATTENTION: Even solitary fish cannot do completely without company. Ideally, platies should be kept with around 4 to 6 individuals of each sex in the tank, while perch will get by with just one pair.
As “Background Animation”:
- Red neon
- harlequin rasbora
- jewelry tetra
- Red of Rio
- Other species of tetra or danios

For life on the pelvic floor:
- armored catfish
- catfish
- Other small catfish species
Variant 2 - guppies
The eye catcher:
- Endler's guppy
- flamingo guppy
- common guppy
The additional stock:
- Harlequin rasbora as a swarm
- Pair of dwarf gouramis
- Schmucksalmer as a swarm
The bottom fish
- armored catfish
- catfish
- Other small catfish
It is important not to use too many animals due to the small tank! Since schooling fish should not be kept fewer than 6 to 8 animals of the same species, the maximum capacity of a small aquarium is limited to a few individual fish, one to a maximum of two species of schooling fish and, in addition, a small number of 3 to 5 bottom fish.
The cold water aquarium
The goldfish is the best-known and most widespread cold-water fish in our aquariums. However, since goldfish do not go well with a particularly large number of fish, it is not always easy to create a lively and varied goldfish aquarium. But it can still work like this:
The eye catcher
- Goldfish, group of 3 or more animals
The additional stock (each as a swarm)
- bitterlings
- moldies
- loach
- gudgeons
- barbel species
- guppies

As a basic revitalization
- armored catfish
- Catfish (with very large water volume!)
The colorful show aquarium
Aquariums should of course primarily be an eye-catcher. Anyone who places particular value on a large variety of colors, but does not want to leave the area of established aquarium fish, will find intensive splashes of color for the underwater world in the various types of neon.
The eye catcher
- Blue neon
- Red neon
- Black neon
Colorful accessories
- discus
- Firemouth cichlids
- clown loaches
- Sumatran mullet
- dwarf cichlids
As soil revitalization
- Glass catfish as single individuals
NOTICE: Again and again one reads about a socialization of neons with scalars. This combination can succeed if the neons are large enough and the scalar has remained rather small. This is the only way to prevent the sometimes predatory behavior of the scalars.
Hard water community tank
Again and again, the revitalization of an aquarium can be guided by purely practical aspects. If you live in areas with particularly hard water, you should choose your fish accordingly.
The eye-catcher:
- Sword bearers in small groups
- Cichlids in pairs or groups

The additional stock, each as a swarm:
- cardinal fish
- zebrafish
- Guinea fowl rasbora
The bottom fish:
- Armored catfish as loners
The shrimp aquarium
In addition to fish, other sea creatures are increasingly found in domestic aquariums. Shrimp are at the forefront. In the past they were seen more as useful additional trimmings, but today they can often score points as real eye-catchers.
The eye-catchers (each as a group):
- dwarf shrimp
- fan shrimp
ATTENTION: Large arm shrimp can be found again and again in aquariums. However, they are not suitable for socializing with fish. Because with their scissor-like tools, a wide variety of fish species are among their prey!
The shareholders (as a swarm):
- guppies
- platy
- Other toothcarp species
Since the shrimp in the center also live on the tank floor, other bottom dwellers should be avoided to avoid competitive situations. Instead, they mainly go together with fish that prefer to live in the middle or even upper water layers.
The seawater aquarium
The salt or seawater aquarium often still has a particularly exotic touch. While setting it up used to be very time-consuming, today the effort is hardly higher than with classic freshwater aquariums. In return, due to the immense size of the natural habitats, there are significantly more fish that can be kept together.
The eye-catcher:
- Parrotfish as a group
- Damselfish as single specimens or pairs
- Puffer fish as loners

The roommates, each as a group or swarm:
- anemone fish
- lionfish
- surgeonfish
- pipefish
The bottom dwellers:
- Shrimp as a group
- Gobies as loners
Notice: At this point, however, the shrimp from the saltwater aquarium should not be confused with the shrimp from the shrimp aquarium. As with fish, there are different species that adapt to salt or fresh water.