I'm playing Fire Red, and I'm curious on when it's a good time to use a moon stone on a nidorina.
Hi! Did a little looking at the levels some moves are learned. I can't say the best level you should use, but maybe this will help? Between level 17 and 55 Nidorina learns the below ones. sumwun said to do it at level 22 for bite and I think that might be best honestly. It looks like you should only hold out if you want Crunch.
-Poision sting [level 18] -Bite [level 22] -Helping hand [level 26] -Fury swipes [level 34] -Flatter [level 43] -Crunch [level 53]