Can Crayfish Live With Fish?

Crayfish (also called crawfish or crawdads) are some of the most entertaining animals you can keep: bulldozing gravel, guarding caves, waving claws at you through the glass. The big question everyone asks: can they live with fish? The honest answer: sometimes, with risks.

Why it's tricky

• They're opportunistic predators. Crayfish will catch and eat fish that are slow, sick, sleeping on the bottom, or small. Bottom dwellers are most at risk.
• They grab. Fins get pinched, especially on slow fish with long fins.
• They're escape artists. Crayfish climb filter tubes and cords and walk out of tanks without tight lids, then dry out.
• Molting makes them vulnerable. After a molt, their shell is soft, and fish can pick at them.

When it can work

• Fast, mid-to-upper-water fish like danios and some barbs that stay out of reach.
• A big tank with plenty of caves so the crayfish has its own territory.
• Smaller, less aggressive crayfish species, such as some dwarf crayfish (Cambarellus), are generally safer with small fish than large species.
• Well-fed crayfish hunt less. Feed sinking pellets, blanched vegetables and the occasional protein. See what crayfish eat.

When it won't work

• With slow, bottom-dwelling or long-finned fish: bettas, fancy goldfish, many loaches, hillstream loaches.
• With shrimp and snails: they're food.
• With another crayfish in a small tank: they fight.

Setup tips

• Tight lid, gaps covered, including around cords.
• Caves and hiding spots, one per crayfish and then some.
• Clean, well-oxygenated water. See do crayfish need air.
• Leave the old shell after a molt; they often eat it for minerals.

Check the law

Some crayfish species are restricted or banned in some states because they can become invasive. The marbled crayfish, which clones itself, is a well-known example. Never release a crayfish (or any aquarium animal) into the wild.

The bottom line

If you want a peaceful community tank, skip the crayfish. If you want a crayfish, give it its own tank or pick tank mates carefully and accept some risk. Many keepers find a crayfish is more fun as the star of its own tank anyway.

Related: Amano Shrimp vs. Cherry Shrimp: Which Belongs in Your Tank? · What Do Starfish and Sea Stars Eat?