Best way to buy feeder snails?

get a tank 10g maybe, fill it with water and get some snails from a local pond and let them breed like for a month, toss in a some plants like maybe grass clippings
these are some common types of pond snails
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if your assasin snails would eat trumpet snails you could do the same thing just with more sand in the substrate

trumpet snail

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trumpet snails do not need a partner to reproduce
they also give birth to live babies
 
ramshorns are the way to go, I'm using a 1g to grow a TON for my assasains...
 
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