How long do crayfish live
Most aquarium crayfish live 2–5 years; Australian yabbies (Cherax) can reach 5–6. Longevity suffers from soft-water molting failure (they need calcium and stable hardness), poor filtration (they are messy), and injuries from tank mates. A species-only tank with good minerals keeps them healthy.
Tank and the predator reality
A single crayfish needs a 20-gal (75 L) tank with hiding caves (PVC, rockwork) and a secure lid — they climb and escape. Keep them alone or with fast, top-dwelling fish only; slow or bottom fish become food. Provide a sand or smooth substrate for digging. Strong filtration handles their waste.
Diet and molting
Crayfish are omnivorous scavengers: sinking pellets, blanched veggies, and occasional protein (bloodworm, shrimp). The key event is molting — they shed the old shell, are soft for days, and hide. Never disturb a molting crayfish; leave the eaten shell (it recycles calcium). Stable hardness and calcium support clean molts.
Why species-only wins
New keepers picture a crayfish "cleaning" a community tank; reality is the crayfish ambushes tank mates at night. Fish with long fins, slow movement, or bottom habits are especially at risk. If you want a lively, odd pet, keep one crayfish solo and enjoy its behavior — do not gamble your fish collection on its mercy.
Beginner mistakes to avoid
- Putting crayfish with fish — they get eaten at night.
- Soft water — molting fails and they die.
- Disturbing a molt — the soft crayfish is defenseless.
- No lid — crayfish are escape artists.