I have an established 10 gal tank and noticed last night I had a new snail! It's not a baby, 3/4 the size of a dime, brownish she'll with dots and kinda a high coiled shell. It looks just like spotted ramshore pics I found on here. How could I have missed a snail this size for this long?? My last new live plant I got was 4 weeks ago. Is that enough time for it to have hitchhiked and grown to this size?