Fish Compatibility Checker

Setting up a thriving aquarium isn’t just about throwing fish together and hoping for the best. Our fish compatibility tool takes the guesswork out of creating a harmonious underwater community by analyzing the specific needs of each species before you make that trip to the pet store.

How Our Compatibility Checker Works

When you use our fish compatibility checker, we dive deep into the environmental requirements that matter most. First up: water parameters. We compare hardness levels (GH and KH), temperature ranges, and pH requirements across species to ensure everyone’s comfortable in the same water conditions. A fish that thrives in soft, acidic water won’t exactly be living its best life with hardwater-loving species—that’s a recipe for disaster.

But water chemistry is only part of the equation.

Next, our aquarium fish compatibility tool examines temperament and size differences. An aggressive cichlid and a peaceful guppy? That’s like mixing oil and water. We flag potential conflicts between territorial fish, fin nippers, and gentle community species. Size matters too—even the friendliest large fish might see a tiny tankmate as a snack rather than a neighbor.

We also factor in social needs, comparing schooling fish (those that need buddies of their own kind) with solitary species that prefer flying solo. Keeping a single neon tetra when they need a school of six or more is stressful for the fish. Our compatibility tool highlights these social requirements so you can plan accordingly.

The Reality of Aquarium Data

Here’s the thing: fish compatibility isn’t an exact science. Some resources like FishBase, SeriouslyFish, and various aquarium databases often provide conflicting information about the same species – it’s one reason why we developed this tool. One source might list a temperature range of 72-78°F while another says 75-82°F. It happens more often than you’d think. Then layer in forums and all kinds of experiences, it’s clear that checking compatibility of fish isn’t a simple one-two.

We really have tried to do our best to average data from multiple reputable sources, creating a middle ground that works for most situations. When information conflicts, we err on the side of caution. Think of our fish compatibility checker as a highly informed friend giving advice and certainly not gospel truth carved in stone.

Regional variations matter too. A species collected from one river system might tolerate slightly different parameters than specimens from another location. Captive-bred fish sometimes adapt differently than wild-caught ones.

There’s also a lot of variables that we can’t control: how you measure hardness, water changes, filters you use, where you live… all these things affect how fish behave in your tank at the end of the day.

Important Disclaimer

We are not responsible for any fish conflicts, injuries, or losses that occur in your aquarium when using this compatibility tool. Every tank is different. Every fish has its own personality. What works in one setup might not work in another, even with identical species.

Our aquarium compatibility checker provides guidance based on general species behavior and requirements, but it cannot predict every outcome. Some fish are exceptions to the rule: the angelfish that never bothers shrimp, the betta that lives peacefully with tankmates, or the supposedly community-friendly fish that turns into a terror.

Always research each species independently, quarantine new fish, have a backup plan, and monitor your tank closely after adding new inhabitants!