Btw the current largest XL fish is the Euphotic Pirarucu, ranking in at a high point of 251.8 Im. The smallest XL being the Silver Shark, ranking in at a high point of 82.5 Im.
Figured it would be best to list the high point for the smallest XL considering that the Coelacanth, a Large fish, can be as big as 80.6 Im.
This might help when it comes to guessing the size of your wanted fish. If it's not 82.5+ Im, chances are it would be Large or smaller.