Not hard to tame, how and tranq arrows work great, taming is short, and in my opinion with just a decent speed and weight they are not me of the best water tames! Unlike most water tames these guys are small, more maneuverable fast and the best part.. they come with their own headlights!
One angler gel refines 24 metal giving 12 ingots. By far the best fuel for refining forge.
To get a lot of angler gel, tame a direwolf and take it inside the strong cave(Snow cave). Clear the area around the first water body near the extrance and kill anglers to get a ton of angler gel. You can go further in the cave of you can handle that to get even more gel.
To make the anglers respawn, move out of the just until to just reach the opening of the dome entrance, wait for some time, and repeat.