Are there any snakes that would stay small enough to be happy in a 10 gallon tank?
Answers:
Green Grass Snake should be fine. And like the previous said, Racers are pretty small too.
http://www.etherzone.com/body.html.
I know this little street goon in Chicago - ratted out his mom,even - says he'll live anywhere. I'll call him for you.
some of the small racer or garden varieties would
male kenyan sand boa.
That size tank isn't really big enough for most adult snakes. You could use it for newborns or juveniles or even as a feeding pen.
