Municipal water supplies need to be disinfected to protect us humans. The primary way this is done is to add chlorine and related products to the water as it is being treated. That is great for us but not good at all for the fish in our ponds.

Fortunately, the chlorine only stays in the water for a short time before it volatilizes, becomes a gas and dissipates into the atmosphere. However, in the time while the chlorine is in the water itself, it can kill the fish.

Generally, there are two approaches to this problem. One is to allow newly filled ponds to set for several days before adding fish. This allows the chlorine gas to move out of the water.

The second approach is to add chemicals which will speed up the process. If you need to get the fish in quickly after filling the pond, you may use one of these products sold at your local water garden nursery. Be sure to read the labels carefully to be sure that you use the right amount of the material and wait the appropriate amount of time to allow it to work.

Fish may be sensitive to extremes in acidity or alkalinity in the pond water. They are also impacted by high levels of nitrates which may build up in a pond especially when it contains too many fish. Test kits are available through most places that sell the fish.