Hello again, I had a clogged pump and found some leeches in the debree, is this normal, are they harmful to the fish, where do they come from, can I get rid of these...

Thanks waterbaby :blink:

Most leeches feed on microscopic animals and plants in the detritus. The ones that are parasites would be stuck on fish, etc. and not in the debris. They are harmless and perfectly normal. Fish eat them so they are more apt to be found in a filter. They can be added to a pond with live plants, fish (in the case of parasitic species), live foods like blackworms (there are always leeches in the blackworms I buy), as well as on the feet/feathers/bodies of animals that visit your pond that were previously at another pond.