Planning a new saltwater tank or adding another fish? Use the checker to compare any two groups, or scan the full grid below. Each square shows how the fish group in that row is likely to get along with the group in that column.
Quick Compatibility Checker
Interactive Compatibility Grid
CompatibleNot CompatibleWith Caution
Hover over or tap a square to highlight its row and column, and the result appears in the checker above.
| Fish group |
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Download the Printable Chart
Bringing New Fish Home
- Test your tank water before you buy. If anything is off, fix it with a water change first. Check pH and hardness, and keep an inexpensive test kit on hand.
- Float the sealed bag in your tank for 5 to 10 minutes so the water inside slowly matches your tank temperature.
- Open the bag over a bucket and gently move the fish into the tank by hand or net. Never pour store water into your aquarium.
- A preventive treatment, such as a broad-spectrum remedy, can help new arrivals cope with the stress of a move and new tankmates.
What If My Fish Are Fighting?
- Fish often guard a patch of the tank as their own. Rearranging rock, plants, and decor breaks up those territories and makes everyone start fresh.
- Add more hiding spots with rock, driftwood, or caves so weaker fish can get out of sight.
- Hungry fish get pushy. Feed small portions several times a day so every fish gets its share.
- If the bullying continues, rehome the aggressive fish. Keep in mind that some species become more aggressive as they grow.
This chart is a general guide. Individual fish vary in temperament, so always research a species and watch new additions closely. Tank size, stocking level, and the order you add fish can all change how they behave.