How long do Fiddler Crabs live?
In a proper brackish setup with land to climb out on, they live about 2-3 years; in fresh water they usually die within weeks.
What do Fiddler Crabs eat?
Feed algae wafers, sinking pellets, blanched veggies, and the occasional frozen brine shrimp 3-4 times weekly. They graze on biofilm and will pick at leftover food in the water.
Enclosure setup
Use a 10 gallon tank with a land shelf of sand and a brackish water section at 1.005-1.010 specific gravity, 72-82°F, and a sponge filter. Add aquarium salt to the water and a tight, escape-proof lid.
Common mistakes with Fiddler Crabs
Deadliest errors are keeping them in fresh water (fatal molting failure), no land area to leave the water, a lid with a gap they climb through, and full-strength seawater that is too salty.
Beginner mistakes to avoid
- Housing them in freshwater, which causes fatal failed molts.
- No dry land area for them to climb out and breathe.
- Any gap in the lid - they climb cables and escape.
- Using full seawater instead of light brackish salinity.