Quote Originally Posted by Hivernica View Post
Rare fishes icons are green.
No. Big Fish icons are green. Not the same thing as rare fish. There are plenty of rare fish that are not green, like Titanic Sawfish, Rhamphorhynchus, etc.

What makes a fish a "Big Fish" is A. it counts towards the Big Fish achievements, B. it does not adhere to the usual bait/level/fish rules, and C. it actually has a mininum gathering rate below which the game will simply not allow you to catch it.