You only really need one because it will reproduce on its own, but you might want more just in case the ine dies before reproducing. If you lived in cali i would give you soome of mine lol... but you can ask your lfs if they have any. I got mine from a petsmart for free.ValerieAdams said:Once I get my tank together, I want to get some Malaysian Trumpet Snails. How many should I get and when should I add them? I have a 29 gallon tank. Also where is the best place to get them?