I'm probably getting a 20 gal freshwater and desided a cleaning crew of snails would be a good Idea (maybe 3?) I was wondering if 2 diff species of snail would mate. I had 2 land snails in third grade that I loved dearly, but then I had a million land snails encrusted on the lid of my snailbox. my dad made me dump them in the woods. long story short, should i stick with one snail?