Pond and ramshorns breed fast and are a good size for most puffers. I raise apple, pond, ramshorns and spixi snails right now. My puffers prefer the pond and spixi (yes I use them as food and no I won't ship them) snails. Pond are easy to get- buy some plants or ask at your LFS- they may just give them to you if you explain what you want them for. Apple are the next most common- often called mystery snails. They don't breed as fast and the adults are the size of golf balls or bigger- not appropiate except for larger puffers. Ramhorns are fairly common too. Spixi are not common, I found them at a local aquarium club meet. It is illegal to ship them across state lines. Avoid the trumpet snails- too hard for most puffers and can break their beak.
