How to Kill Leeches in a Tank

Leeches are external parasites that can cause their hosts to become weak, infected with secondary infections and even die. The leech's main objective is to feed on the blood of the host. Leeches tend to be more active during the dark hours and will leave circular wounds on the skin. One leech in a fish tank can multiply into more, since leeches can reproduce asexually. If there is one leech, then it is best to assume there are more. The removal of the leeches from the tank is essential, as they can kill all living creatures in the tank.

Things You'll Need

  • Tweezers
  • Salt solution
  • Trichlorofon
  • Potassium permanganate
  • Measuring cup
  • Freshwater puffer
  • Jar
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Instructions

    • 1

      Remove fish from the tank and inspect the fish for leeches.

    • 2

      Give the fish a bath with a 2.5 percent salt solution for at least 15 to 20 minutes, if there are leeches attached to the fish. This will often cause leeches to die or become weak. If the leeches are still attached to the fish after the bath, they will have loosened their hold on the host; use tweezers to remove them.

      The bath water should be the same pH and temperature as the tank water. Do not use this method on salt-sensitive fish.

    • 3

      Remove the plants in the tank. Treat the plants with potassium permanganate for 1 hour. Use approximately 5 mg per liter of the solution to treat the plants. The potassium permanganate will kill any leeches hiding within the plants.

    • 4

      Treat the entire tank with Trichlorofon (also known as Metriphonate), an organophosphate insecticide, to get rid of leeches. Use approximately 0.25 mg per l of water in the tank. This product is usually not available in a pet store but can be purchased from your local vet.

    • 5

      Purchase freshwater puffers to eat the leeches.

    • 6

      Trap the leeches using a jar trap that has a piece of meat in it. Once captured in the trap, the leeches can be killed manually.

    • 7

      Remove any hosts from the tank for about a month or two. This will cause the leeches to die slowly, since they require blood for survival. This is often the last option, if every other solution fails.