Egg-Bound Female Koi: Causes and Management

Condition

Female koi extremely fat since spring, finally released eggs (eaten by pondmates). Owner wants to understand egg-binding.

What Is Egg-Binding?

Female develops eggs but cannot spawn (no male, wrong temperature, stress, obstruction). Eggs are normally reabsorbed. If not, female becomes egg-bound (dystocia), risking infection, organ compression, death.

Causes

• No mature male present.
• Temperature fluctuation (spawn trigger 65–75°F).
• Poor nutrition (lack of protein/fats for egg development).
• Physical obstruction (tumor, adhesions).

Treatment

1. Natural: Provide spawning brushes/mops, raise temp to 72°F, ensure male present.
2. Hormone injection (carp pituitary, Ovaprim) – vet only.
3. Manual stripping – expert only; high risk of injury.

Prevention

Balanced diet year-round, proper male:female ratio, seasonal temperature cues, spawning media.

Your Pond

30 koi in small pond → overcrowding stresses fish, inhibits spawning. New 15×7×4 ft pond will help. Move fish gradually.