Shellos is normally evolving at level 30.
I have allready trained mine to level 53, and have not seen any evolution screen yet.

Could you tell me a bit more about how you've been leveling up your Shellos?

If you have been feeding it rare candies to level up, please try gaining experience via battling to level it up instead!

I have been leveling it up in cerulean cave, using exp share. I tried with a few candies to pop the levels to see if it would trigger evolution, and i tried stones to evolve.

That's all very useful information, thank you!

Please try to evolve your Shellos by fighting directly with it in combat and obtaining enough experience to reach the next level. Let me know here if this helps!

23 minutes ago, Ayroo said:

That's all very useful information, thank you!

Please try to evolve your Shellos by fighting directly with it in combat and obtaining enough experience to reach the next level. Let me know here if this helps!

Leveling it up that way, did not trigger evolution ether.

Before level up

After level up:

Thank you very much for your patience! Could you next please try to faint the Shellos and then level it by directly fighting with it again?

If the above doesn't work, please try to trade the Shellos back and forth with another character, and then try leveling it directly again.

This is an infrequent bug but it does occasionally happen and is actively being worked on, thanks again for your cooperation!