Best to use a quets noble tame box. Since they don't run from you its easy to catch them and tame them inside since there mostly over water. Just remember not to move the quetz once it's inside the box or it will simply go through the walls..
Ever need lots of raw fish. Easy! Instead of swimming around in the water risking getting attacked by megapiranhas, simply make a saddle for your Pelagornis, Ride it into the water, and it one shots every small fish.