Depends on the fish.

Springers, summer kings, or summer steelhead's that are loaded with fats. no.

Puget Sound and fall fish, yes. I think I followed SZ's advice and put a 1/2 a TBSP of EVO in the half-pint jars and would use a full TBSP for a full pint jar.

I'm with Dave in that I'd leave the skin on. Pre-cut the fillets so they will fit in whatever jars you are using. Makes it easier with the skin to get the fish in the jar.