Last year I picked up 2 mystery snails and was lucky enough to get a male and a female. They bread and I hatched out a few bunches of eggs so I have mystery snails now in all 8 tanks, at least 4 or 5 in each one. Over the last few weeks though the ones in the 36BF started climbing out. I put one in a different tank and had a clutch of eggs that very night so I was assuming she was looking for a place to lay eggs. A few days later I found another one, the a week later a nerite climbed out. This morning there were 2 more MS on the carpet. So far only the nerite died. I do not know how to close up the tiny little gap in the cover where the in and out flow for the filter is. I thought maybe there was a water quality issue even thought I do a 10 gallon change at least twice a month but ammonia is 0, nitrite is 0, and nitrates are around 20 this morning and probably only that high as I dosed easy green yesterday. It does look like they are only coming from the 1 tank, but in that particular tank they have grown bigger than the other ones. Other than using some sort of plastic wrap to fully cover the rest of the hole is there anything I can do to discourage them from escaping? I do not think they are lacking for food. I drop in a zoo med nano every week for calcium. Eventually I will miss one if I haven't already or worse step on one before I see it.