Fjordur, best mount so far.

Aquatic speed is great.

Taming fairly basic, ghillie or slow and patient.

Find good clefts and areas, or maneuver into a pen/trap area. Like equus, you feed them the fish baskets.

For the basket, in engram list, top of list is highlighted island, deselect and your list should expand.

Fishbasket should be available to make and use the area in Midgard both blue forests have fish and mats for baskets, as well as the shadowmanes spawning, at NIGHT. They have a pack bonus, so you might need to clear the others or poke/aggro a good one, have a fast mount or flyer if possible.