it does not evolve enymore when it is a blastoise.
blastoise doesnt evolve.
The level Squirtle evolves into Wartortle Is the exact same level as it was introduced Lvl 16 then at lvl 36 itll evolve into blastoise
Level 36.
Wartortle evolves at level 36 into Blastoise.
It evolves into Blastoise at level 36.
graveler doesnt evolve at a level, you evolve it by trading.
Wartortle evolves into Blastoise at level 36.
Level 20.
Level 55
level 30
level 28
Level 18