We have two Racerback Nerite Snails in our freshwater tank with four guppies. We haven't added anything new in 9 months (since before Covid). We clean the tank every week (10gallon). I noticed today a bunch of small snails crawling around. My understanding is that nerites can't reproduce in freshwater, but we haven't added anything new to the tank. I've attached some photos. They are pointy shelled. Any suggestions??? Thank you!