Fish Measurements: Which is more common?

[PotatoFish]

I have a question about fish measurements. When you hear that a fish grows to a certain length, what measurement are they probably using? I hear a lot of descriptions for how big a fish will get, but what do they mean when they give those numbers?

Is it the green line, from the nose to the base of the tale fin?

Or is it the purple line, from the nose to the tip of the tale fin?

[BenA]

I believe that it is one end to the other, i.e the purple line. See this exhalent site for information about most fish.

Seriously Fish — Feeling fishy?

[lefty o]

in general, it is the purple line. now if we started talking the old fashioned tank stocking, it is inches of body length minus fins, so the green line.

[FriendlyLoach]

Yeah, the purple line. 

[AdamTill]

Purple if someone is trying to sell you the fish, green for standards and competition ie https://thegoldfishcouncil.org/product/can-am-all-goldfish-show/

[PotatoFish]

Thanks for all the input!

What about when people speak in general, for example one hobbyist to another about things like how big a certain fish gets?

[lefty o]

in general when people discuss the length of a fish, its from nose to end of tail, your purple line.

[PotatoFish]

9 hours ago, lefty o said:

in general, it is the purple line. now if we started talking the old fashioned tank stocking, it is inches of body length minus fins, so the green line.

Ah, I missed the the "in general" bit. I guess I can see how saying the total length of the fish can be helpful in gauging whether it will have issues turning around.

Edited January 11, 2021 by PotatoFish
spelling

[AdamTill]

Sort of. The nose to peduncle (short) line is actually more useful though, because you can compare long to short finned fish more usefully. Long flowy fins don’t really affect mass (or turning distance) much.

Edited January 11, 2021 by AdamTill