Can you always stop a Pokemon evolving?

Question

I traded all three starter Pokemon from fire red to leaf green.. I want to keep my squirtle at its first evolution and was wondering why it keeps evolving even when I press B?

Is it something to do with disobeying me? Can I stop this in anyway? Thanks

Comments

Pretty sure pressing B always works for leveling up, but not for stones or trading.

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Did you press B at the very start that might be why.

Answer 1

You can have the Pokemon hold the Everstone. You can get it from Oak's aide in the Pokemon Centre outside The Rock Tunnel at Route 10. You need to obtain 20 Pokemon before he'll give it to you.

As for why Squirtle kept evolving; no idea.