READ! it's a bad idea, you want a vivarium get a frog or a crab, fish=aquarium, yes if it's moist enough the snakehead will survive on land for a while and you might find it in time, but it's not a good thing, you'll still have a very stressed out fish ,messed up slime coat, injuries, ect. and this will lead to a very unhealthy and eventually a dead fish.
plus your cutting back big time on the swimming space, and snakeheads need room to move, all and all as everyone has said this is a BAD idea, sorry but your gonna have to deal with that, if your not going to except the advice given why bother asking ?
I have several planted vivariums myself,99% of fish just arnt a good match for them , with a large enough "pool" area you might pul off some guppies or something like that but that's about it,