How to Keep a Snail or Slug for a Pet
Finding Snails and Slugs
Snails and slugs can be found cool dark places, such as under logs, under porches or crawl spaces, and gardens (especially ones that grow fruits or vegetables). They are also nocturnal, so you have better odds of finding them at night. My first pet slugs were found sliding along near the back porch while camping out in my cousins' back yard as a child. They were huge spotted garden snails (much like the one in the above picture), each about four to seven inches in length. My cousins were pouring salt on them, which in case you didn't know is a toxic substance to snails and slugs, so I felt obligated to rescue them!
Snail and Slug Habitats
Your pet snail or slug can be kept in a small jar or aquarium depending on the size of the specimen. Dirt, leaves and rocks can be placed inside to make your mollusk feel more at home. Be sure and moisten the soil a few times a week so that your snail or slug is properly hydrated. Like all animals, snails and slugs expel waste so changing out the soil in your pet's cage is important. Another important thing to remember is that snails and slugs constantly secrete mucus, which enables them to move around but can also leave very thick deposits all over the surface of their cage so it is vital to wipe down the glass daily. For this reason I would suggest only keeping one or two snails or slugs as pets (I made the mistake of trying to house seven of them).
Feeding Your Snail or Slug
As you can see by the above photo, snails and slugs love vegetation which is why they are commonly considered pests to most farmers and gardeners. You can feed your pet vegetation from outside: leaves, grass, clover, just about anything will do. You can also feed them leftover fruits and vegetables from your fridge (my slugs were particularly fond of bananas).
The Dangers of Overpopulation
Snails and slugs multiply rapidly, another reason why they are a scourge to many farmers and gardeners. They are also asexual which means they contain both male and female sex organs so they do not need another snail or slug to procreate. If you're not careful, you're tank can become overrun with snail and slug babies! Take the babies outside, far away from your garden if you value it, a wooded area will be sufficient so that they do not bother anyone.