Species conflicts
Recorded conflicts between the selected fish are shown clearly.
Fish Compatibility Checker
Check whether freshwater fish can live together and whether your aquarium meets their needs.
Step 1
Select fish
Optional: sign in to import an aquarium and its saved fish into this check.
Current fish
Selected fish
Search for a fish to start the check.
Optional
Check your aquarium too
Freshwater compatibility
Check the fish and the aquarium
Compare the fish you want to keep, their group needs, and your aquarium conditions. Temperature, pH, and general hardness are considered when information is available. If something cannot be checked, the result will clearly say so.
The checks behind the result
Group and social requirements
Selected quantities are checked against documented minimum group sizes.
Aquarium size and length
Available minimum volume and length requirements are compared with your setup.
Temperature and water values
Temperature, pH, and general hardness are checked when matching values are available.
Available information
If an important detail is not available, the result explains what could not be checked.
How to use the checker
Three steps
- Select the fish.
- Enter quantities; aquarium details are optional.
- Review conflicts and required changes.
Coverage and limitations
Read each result in context
A compatible result does not replace observation and responsible care. Aquarium layout, breeding behaviour, and individual fish can still change how a community behaves. A setup issue and a recorded species conflict are shown separately.
Fish compatibility FAQ
What does fish compatibility mean?
It means the selected fish have no recorded species conflict in the checker and that the entered aquarium conditions can support them.
Can compatible fish still need a larger aquarium?
Yes. A compatible pair can still need more volume, length, or a larger group than the aquarium provides.
Why does group size affect the result?
Some species need to be kept in groups. The checker compares the selected quantity with the documented minimum when that value is available.
What happens if a fish is not yet supported?
The checker shows that more compatibility information is needed instead of treating the fish as compatible.
Does the checker consider temperature and pH?
It checks temperature, pH, and general hardness when matching values are available for the selected fish.
Can I use the checker for more than two fish species?
Yes. Add the species you want to keep together and enter the quantity for each one.
Does “compatible” guarantee that the fish will never show aggression?
No. Aquarium layout, individual behaviour, breeding, and care can still affect how fish behave.
Can I check the fish already in my aquarium?
Yes. Sign in, choose one of your aquariums, and the checker loads its saved setup and fish for review.
Can I save the result?
You can save the current fish selection and aquarium inputs. The checker recalculates the result when you open it again.
How often is the compatibility data updated?
Information is expanded as additional compatibility records are reviewed. Combinations without enough information are shown as needing more information.