Q: My pond was almost completely covered in algae earlier this month. With the advice of a local store, I treated my pond with an algaecide. Needless to say I suffered a terrible loss! What killed all of my fish? – Marie of Florida
A: More then likely your fish loss was due to oxygen depletion. It is very rare that an EPA registered “Aquatic Approved” chemical will cause a fish kill.
What causes oxygen depletion?
After a chemical application, algae and aquatic vegetation start to die and begin to decompose. The decomposition process requires great amounts of oxygen and can sometimes, like in Marie’s case, be harmful to fish. The chance of oxygen depletion is much greater when a pond is not maintained on a regular basis or when water temperatures are at their warmest such as the dog days of Summer. The warmer the water, the less oxygen it can retain.
How to treat your pond and keep your fish safe:
We recommend that you treat your pond in sections. The generally rule of the thumb is to split your treatment in to 3 parts or thirds. Treat 1/3 of your pond starting from shoreline working your way towards the middle. Allowing 5-7 days between treatments will greatly reduce, if not completely eliminate the chance of fish kill.
NOTE: Always follow the label rates on the container!
Reduce Oxygen Demand with an Airmax® Aeration System Airmax® Aeration adds oxygen to your pond reducing fish kills, while improving the overall health of your pond and fish.