snail tank

[A.K.A Zak]

i'm going to the lfs today to pick up a 10 gallon tank, a undergravel filter, and a heater. i'm filling the 10 gallon tank up half way, are the snails likley to escape from a half full tank, and can i put a gramie in without worries? thanks for your help.

 

[A.K.A Zak]

and can they survive without a tank light, i will still have everything else i would need for a tank.