So, to clarify the above few posts:
Blanka balls must be blocked standing and not crouching to be punishable mid-screen.
You can punish with;
-Dash forward > 1x LP Rekka then finish with HP Rekka.
-Reversal timing MP Rekkas, where the second Rekka connects.
-Reversal Ultra 1 just hits Blanka’s hitbox with the second hit and goes into the animation for 435 damage with full Ultra, but be wary of this, as in some cases (about 15% of the time) it will whiff even if you have reversal timing, why that is, I don’t yet know. Anybody have any idea why that is?
-EX Blanka Ball can be punished in the same ways, though I am not entirely sure if it is slightly more punishable.
In the corner you can punish with pretty much anything, except the problem is in timing it so that you hit him when he’s landed, instead of catching him in the air. You can punish blanka balls on hit with tonnes of room for error.
This post brings the question, wasn’t there a punish guide with Fei somewhere on the board? Is that linked to in your mega thread Nosone??