Can't select a Pokemon which can the attack Sleep Powder [Goldenrod City]

[Filex]

Hello everyone,

 

I was happy to have finally a Pokemon with Sleep Powder, but when I will continue the Goldenrod City Main Quest to challenge the gym leader Witney I can't select my Pokemon which can this attack.

 

Here an example:

 

Edit: It's done, I needed Fresh Water.

Sorry for making the topic too fast.