What is Carp Pox?
Carp pox is a skin disease caused by a virus (Cyprinid Herpesvirus-1).
It creates smooth, white, waxy lumps on the fish, usually during winter and early spring when the water is cold. These lumps often shrink or disappear as the water warms up.
Carp pox doesn’t normally harm the fish and is much more unsightly than dangerous.
Fish that get it usually carry the virus for life, but the symptoms only show at certain times of the year.
What does Carp Pox do to fish?
- White or milky patches appear on the fins, body, or head
- Lumps are smooth, waxy, and feel firm
- They may leave scarring when they fade
- Large patches can join together and cover big areas of skin
Most fish live normally with small patches.
However, if lumps form on the mouth or gills, the fish may struggle to feed or breathe.
Very severe, long-lasting infections can:
- Slow growth
- Thin the fish
- Affect the skeleton (rare)
How do we minimise Carp Pox problems?
There is no treatment, but you can prevent it becoming a big issue by:
✔️ Reducing stress
Carp pox flares up when fish are stressed by:
- High stock density
- Poor habitat
- Poor water quality
✔️ Managing stock levels
Fewer carp = less stress = fewer outbreaks.
✔️ Monitoring water quality
Cold water triggers the disease, but good water quality helps fish cope.
Check:
Simple fishery management = fewer visible lesions.