Typically when you get a range of fish sizes from the supplier, the majority of the fish will be on the small side of the size range, that's just because how they are measured (by thickness not by length - there is a formula that determines how long a fish is in relationship to it's width).
Do they size their fish based on width because they are separated into size classes using a screen? (Wherein, the ability to "pass" or "block" would be determined by the width of the fish?)Correct.
https://www.fishfarmsupply.ca/products/floating-fish-grader?variant=31981211156562You are on your own to find what width of what species equals a certain length.
THEN you take 100, 200, 500, 1,000 fish by hand, count and weigh them. That is what the guys like me buy - we buy the fish by weight. Say if I order 10,000 2.5-4" BG they weigh them and put them in the haul tank. A LOT quicker than counting them.
