I have a ~1000 gallon pond in my backyard near Houston, Texas. The pond is stocked with 2x 16-17" Koi, 8x Goldfish, and some cichlids in the summer. It is filtered by a box filter at the bottom of the pond, with water coming in through a screen at the top, going through a foam layer, then through some bio - balls, and finally to the pump, where it is pumped to a waterfall. However, every time i clean the filter (once every 2-3 weeks usually), there are ~20 1" leaches in the filter, sponge, and bioballs. I have never had any leaches on the fish. My questions is what they could possibly be eating? They are growing and breeding there, i assume, considering i remove all the ones i find, and they keep coming back. At first i wondered if they werent actually leaches, but when i place them on my hand, they suck my blood, so they are definately leaches. The only other organisms in my pond are some frogs, a bunch of ghost shrimp, and some pond snails. Any idea son what they could be eating?
