|Could you please explain what Flashing is?.......My Koi fish will occasionally jump or do little twists in the water....I always thought they were just playing....is this the sign of a disease though? I have an 8000 gallon pond with superb water quality.....thanks Paul Chapman
Flashing is a condition in which fish quickly lay over, then dash their sides against something in the pond. Often, they are trying to dislodge a parasite from their surfaces. In many other instances, they have been put into new water, water with a new pH, water with some Chlorine, or water with some other chemical irritant (high Ammonia levels for example.)
Flashing is normal in fish, when you see it once or twice per day per fish that would be 'okay' but if you see fish flashing two at a time in a pond it's more than coincidence and water quality, and CHANGES in water quality should be evaluated. For some people, it's simply the daily fluctuations in pH that cause the problem.
In other cases it's a parasitic issue. Several parasites cause profound flashing including but not limited to Costia, Flukes and Trichodina.