Hi- we have a 75 gallon outdoor pond and we have a turtle instead of fish -- we somehow have gotten leeches in the pond and need some guidance to find out how to get the pond leech free - can you help me? thanks

Turtles are notorious for transporting parasites into a pond environment and are commonly carriers of Salmonella as well. Most water gardeners who are primarily fish fanciers do not encourage turtles, since the larger and more aggressive species (painteds and red-eared sliders, especially) are very efficient predators.

There are a variety of "whole pond" treatments available for parasitic infestations; these vary with the predominant parasite. Even with that, any visitor to the pond from elsewhere following a treatment (birds, bullfrogs, raccoons, etc.) will restock it with fresh crawlies fairly quickly. The best defense here is optimum fish health.

Bare liner ponds, while not as pretty or "natural" as rock bottom ponds, tend to be less likely to encourage leeches, which prefer warm, slow-moving or stagnant water.

The best interim solution, however, is salt. It has the advantage of being nontoxic to fish and filtration, and in the right concentrations, actually helps fish conserve energy otherwise spent in maintaining osmotic balance. Leeches are sensitive to fairly low concentrations. Unfortunately, many other parasites are capable of developing a tolerance to it. A level of 2.5 pounds per 100 gallons is effective as a "tonic" in early spring, but will harm most aquatic plants. It's best used before your plants wake up, and then diluted down with water changes as the season begins. I like to maintain a fairly steady concentration of 1.5 lbs per 100 gallons. It is a reasonable compromise between fish and plant health.

Bob Passovoy
President
MPKS