Nerite snails are algae CHOW HOUNDS! Zebra nerite are small but very pretty tank additions that are plant safe. Avg size is approx 1/2", nice youngsters! They will be shipped in a Kordon Breather bag inside of a styro lined box with a heat pack if needed. Shipping is generally done on Tuesdays via 2-3 day Priority Mail. BE SURE SOMEONE IS AVAILABLE TO RECEIVE THE PACKAGE. I package extremely well but in harsh weather packaging can only go so far to protect them. DOA Policy (Rare but still need to address it) 100% LIVE ARRIVAL GUARANTEE Priority Mail... Doa will be replaced or credit given. Replacement shipping paid by buyer. I pack my packages very well so buy with confidence!