Fish Compatibility Checker
What fish can I keep together?
This is a starting-point guide for common freshwater community approaches, not an exhaustive species-by-species database -- always research the specific fish you're considering before combining them. Answer a question and we'll point you toward the right general approach, or browse the table below.
| Result | Best for |
|---|---|
| Peaceful Community | The safest, most widely compatible mix |
| Semi-Aggressive Community | For a bit more personality and activity |
| Species-Only Tank | For fish that don't play well with others |
How this quiz works
The Fish Compatibility Checker asks what kind of stocking appeals to you: the safest, lowest-risk community, a more active and personality-driven community, or a specific territorial or solitary species. It points you to a peaceful community, a semi-aggressive community or a species-only tank.
Why these questions
Compatibility depends on temperament, size, water needs and space. A peaceful mix of small schooling fish and bottom-dwellers is the lowest risk, semi-aggressive fish need more research and more room, and some species do best alone or with their own kind. The question finds the general approach, not a list of fish.
What the quiz cannot see
It cannot check any two species against each other. Temperament varies within a species and with tank size, group size and layout. Look up each species you want, check adult size, water parameters and behavior, and use the Aquarium Stocking Calculator for a stocking guide.
Before you decide
Check that all your fish want the same temperature, pH and hardness, keep schooling species in groups of the size they need, add the most aggressive fish last and plan for the adult size of every fish. Have a plan for a fish that does not get along, such as a second tank or a return to the shop.