No such thing.It's a matter of personal preference.Smelt is about 3-11 inches and they are awesome eaters.Most people keep crappies in the half to 3/4 lb. range,yet others,larger.That also depends on geographical locations too.Walleye's I keep are mostly in the 14-18 inch range or fish up to 2 lbs.Pike mostly up to 10 lbs for steaking them out and smaller pike for pickeling.Bluegills I keep mostly are between 5-8 inches for eaters.
Everybody is different.You'll have your preferences as you catch more.Good luck and good eatin'!