From previous observation, it took Ramshorn snail 9 days to hatch and another 26 days to mature (i.e. 35 days to complete a generation). How fast do they breed ultimately determined by how many eggs do they produce and how often do they produce. I did one small experiment. I placed 9 adults Ramshorn snails in a plastic shoe box, I feed they enough food they they would not be able to finish in a day. I change out 100 % water daily (from other aquarium) so to keep the ammonium low. They average 15 to 20 eggs (From my previous observation, they are about 10 to 12 eggs). The larger number of eggs are attributed by bigger snails (1 1/4 inch in diameter. They usually are able to lay eggs when they are about 1/4 inch in diameter) and unlimited amount food. How often do they lay eggs?
Day 1: 0 clusters (no eggs on the first day because they were on starvation before moving them to the breeding box.)
Day 2: 5 egg clusters
Day 3: 18 egg clusters
Day 4: 45 egg clusters
That’s about 5 clusters every four days per snail. i.e. On average, it will be 18 baby snails per day for each snail. Each baby will be able reproduce in 35 days. Those 18 babies will produce 324 eggs and each day there will be 18 more snails mature and produce 324 eggs. That’s lots snails!