I will talk to my local petsmart about it and see if they will allow me to get some. My only worry would be them breeding and creating an over-infestation that the assassin snails could not keep up with. I will be getting this filter in the 30 gallon size. Is this a good filter? What would be the guidelines for this one? It uses foam, activated carbon, and biomax, which I guess is the ceramic biomedia: http://www.petsmart.com/product/ind...ion+&+Circulation&f=PAD/psNotAvailInUS/No