People often ask if their egg clutches are fertile so here is an example of an infertile clutch (left) next to a fertile clutch (right).
These two clutches were laid within 2 days of each other. The one on the left is “bad” or mostly if not completely infertile. See how the egg cells are small and not very bubble like? Two other tips on detection: 1) smell a clutch that you suspect is bad if it’s been at least two weeks. Infertile or bad clutches have a distinctive smell while healthy/fertile clutches do not. If the clutches are sitting on a damp paper towel, do you see a red/pink stain under one? Only infertile clutches will stain the paper towel. You can see in the photo above that the left clutch has stained the paper towel pink underneath it.
The one on the right is very fertile and it will likely hatch In the next day or two. It would still be necessary to wait a week to 10 days to be able to tell this as egg development is unclear until that much time has passed. About 3 days before hatching, a fertile clutch will start to change color to look moldy prior to hatch. You cane see the color changes in the Mystery Snail Egg Development page link below. It takes anywhere from 10 days to 4 weeks for an egg clutch to hatch based on temperature and other conditions.
Florida Mystery Snails 
What if your clutch has a smell but is not turning the damp paper towel pink at all? It will be 10 days the 13th.
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They shouldn’t smell bad. If it does, it’s probably infertile.
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Obviously if I wasnt new to the experience of mystery snails I wouldn’t be here.
I have a male and female in an aquarium. They laid a clutch for the first time in the 3 months we had them. I had to relocate my clutch and I’m not sure if I’m doing everything correct. I have them in a tupperware container, its sitting near the heater, and filter. I also check on it daily so I know it’s safe.
It’s been about 2 weeks since lay. I’m keeping it moist but they are still hard, and pink. How much longer should I try before giving up? 2-3 weeks?
Thank you for reading.
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Depending on temperature it can take up to 5 weeks to hatch. No harm waiting longer.
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I have a baby beta fish. About the width of a pinkie but shorter. Will it eat the baby mystery snails?
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I can’t answer that for certain. Some bettas leave mystery snails alone (especially if raised with them) but others may harm them. I have seen young bettas eat ramshorn snails but not mystery snails personally.
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I got two clutches but the thing is I found the clutch a week after I found the first one. Should they lay that so early?
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If you have a prolific female or more than one, yes. I have had some give me eggs once every 7-10 days and others one big clutch every couple months. It varies by snail.
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I have 5 mystery snails, 2 of them are thumbnail sized 2 other are about an inch 1/2 and one is 2 inches. I don’t know genders but have 3 batches of eggs. one large on the front of the tank and two small near the back.
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Would that be one female? or multiple?!?!
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Could be either and usually mystery snails have to be at least quarter size to breed.
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My snails have 2 clutches from different moms but how big are the eggs because Its small in comparison to the second is that normal ??
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It can be. Egg size can depend on the size of the mother. Size of the clutch and (likely) the diet each female consumes. Medium and small clutches tend to have larger eggs and babies than very large clutches.
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Thank you, this page has been very helpful. After the babies hatch, what type of plant life should I place in the tank fir them to survive. My 1 snail has laid 5 cluches in 1.5 week time frame. After the first clutch I put the male in a different tank.
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I use duckweed, Java moss, hornwort and guppy grass in my snail tanks. The babies love eating duckweed so I try to always have some in with baby snails.
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Soooo my clutch kinda smells like mold… does that mean it is infertile orrr are they dead…
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Could mean either. Healthy clutches don’t tea smell much
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Should I keep my snail eggs warm or cold?
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It doesn’t really matter… warmer temperatures speed up incubation. Eggs can take anywhere between 9 days and 5 weeks to hatch. I keep mine in a room that stays around 74-80 and they hatch in about 2 weeks
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I have been keeping them on the side of the tank, but every time I take the lid off I scratch them.
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They will hatch on the side if you don’t damage too much by scratching…
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My snail laid her eggs in the water and hung them underneath my filter, will they still hatch? I’m sure momma knows what she’s doing. Why didn’t she lay them above the water like other mystery snails? Curious.
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Unfortunately no, they won’t hatch. The embryos need air to develop. She might get it right next time. Submerged eggs can only hatch if it’s for a very brief period (like the eggs fall in the water and the owner notices quickly and picks them up and puts them in an incubator).
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