Hi again and please forgive my delay in responding as I was finishing up another question.

The symptoms you are describing, slimy and seem to have skin lesions, are an indication of a bacterial infection and possibly a parasite problem.

The algae in itself is not necessarily a sign of water quality problems but is more an indication of excess nutrients in the water caused by overfeeding, excess lighting/sun and decaying matter in a pond.

To put the algae under control an alage removing product can be added to the water.

These types of additives can be easily found at most pet stores.

As for treating the fish disease unfortunately you'll have to take the pond out of it's peaceful winterized state and take some steps.

The first thing to do is begin by changing 25% of the water in the pond. With the water change add some pond salt. Any brand will do just follow the directions on the product label for dosage instructions. Pond salt will help fight off the bacteria, any parasites that may be present and serves as a general tonic.

After the above has been done begin to treat with a medicine called TetraPond Pond Fish Treatment which I believe is sold under the name of Desafin in Canada.

The TetraPond Treatment is a wide spectrum medicine which treats a variety of fish diseases including bacteria and parasites.

As a precaution I'd also recommend that you have the water tested for ammonia, nitrites and nitrates. Results should indicate ammonia and nitrites=-0- and nitrates 20ppm or lower. My reason for suggesting that the water be tested is that unfavorable water conditions are usually the cause of fish disease. Deviant results would indicate the need for a series of weekly 25% partial water changes until the water tests indicate all is normal.

Best wishes and please let me know if you have any questions.

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I'm sorry I didn't realize you have plants in the pond.

Yes a full/normal dosage of pond salt will have an ill affect on the plants so usually what is done is 1/2 the amount of the recommended dosage is administered.

Yes Kosher salt is an acceptable as a substitute for pond salt as is any salt that does not contain iodine.

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The best thing to do is follow the instructions on the salt's product label as each product has differing strengths. Most pond salt product will give a dosage amount for planted ponds and non-planted ponds. Between 2 different pond salt products I've seen such dosage variations from 1 1/4 cups per every 100 gallons of water to 1 cup per every 120 gallons of water hence it's best to follow the instructions for the particular product being used.

Add the salt after the 25% water change. If you decide that you'd like to continue using pond salt, which isn't a bad idea, you would then only add the amount of salt that corresponds with the amount of water being added. It's not necessary to add additional salt if compensating for evaporation as salt does not evaporate.

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If you've decided to use Kosher salt, which by the way is an economically sound decision, I would recommend using 1 cup per every 150 gallons of water. The plants should be safe at this dosage.

So for a pond your size, 10,000 gallons, you'd add about 66 cups of salt which equals about 14 1/2 pounds of salt.

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