i bought about 150 for my 75 gal
. havent received them though and the ebay seller aaronssales said they had some problems with moving, tanks destroyed, and also needed to collect more. so i would watch out for this seller until later.
i have less than a dozen of them now. evry othr day, when its feeding time of the frozen mix recipe, i would let the mix thaw out then let ONE DROP of liquid hit the water. Its amazing that these snails immidiately pick this up and suddenly u have snails all over the tank. 8O