Yes, it’s true that salt does kill leeches, but I wouldn’t suggest using an excessive amount of pond salt because this may affect the health of your koi. Excessive salt in your pond is very harmful to your fish if they are not accustomed to it.

Why does salt kill leeches?

Salt is one amazing mineral. People have been using salt for ages to preserve food because of its ability to draw water out of cell membranes. This is why salt is so damaging to leeches.

Leeches’ skin, like slugs, is permeable. What this means is that their skin is made to let moisture easily flow in and out of their body. Remember when I said that salt has the power to draw water out of things? It starts causing all their cells to lose moisture, shrivel up like a raisin, and then die. That’s why salt is so effective at killing leeches.

Too much salt will harm your fish

If you over-salt your fish pond to try to kill leeches, you could actually burn them and cause tissue damage. Add too much salt and it will lead to death. This is because koi and goldfish are freshwater fish and are not meant to live in high salinity waters.

Get rid of leeches without using salt

To the best of my knowledge, there is no effective leech treatment sold. Since I don’t recommend using excessive amounts of salt, what other alternatives do you have? Well, there are a few tricks I recommend if you are determined to get rid of those leeches in your pond.

Get rid of leeches with a “leech trap”

Years ago I was told by another pond keeper to try a piece of red meat in a coffee can that has the plastic top with a 1″ hole on it. The red meat will act as a lure and will draw the leeches in without affecting the fish. I have actually used this method and found it to work, but you have to be patient and it does take some time. I would suggest checking your “LEECH TRAP” each day and to change the red meat out daily.

Clean out the sludge in your pond

In my opinion, the best way to remove a pest problem is to remove either their source of food or their shelter. In this case, we are doing the latter. Leeches breed and live in all the sludge on the bottom of your pond. By clearing out all that sludge, you essentially evict them from their homes out onto the streets. To make matters worse for leeches (or better for you), you’ll soon see why life is hard for a leech in a pond with nowhere to hide.

Fish love to eat leeches

Believe it or not, the biggest predator to leeches is actually fish! Leeches are very similar to worms, except that they get nutrients from blood instead of dirt. If you’ve ever seen fish go after worms, then you’ll know exactly how much they love these little guys. Fish are the perfect predators for leeches because they are rarely still long enough for leeches to bite down on.

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