Burbots (Made in Finnish) are one of the larger fish you can catch. They are just as common to catch as a bream but in much less quantity. You can usually catch 1 - 3 burbots in a net if it is placed on a rapids tile.
The burbot is also one of the best fish to carry around with you while you hunt because (like all fish) it is very nutritious, yet is the lightest of the "big" fish.