Some Critters can be a challenge to obtain. But, it is not impossible either.
The best way to get one is to share Mystery Critters with your Friends in the hopes that they will turn around and share one right back! Gift mystery critters to your neighbors, and they will send them back to you.
Having more friends and neighbours that play Pot Farm will help too! (Hint, you can find awesome friends on the Pot Farm Fan Page on Facebook.)
This system is in place to encourage making friends in the game and helping one another out by sharing the wealth.
Right now, this is the only way to get a specific critter. Keep your eye out for other ways. You never know, we are always adding features here and there!