I easily tamed one by luring it on a sand bar. My make shift tamming pen was made of 4 foundations, 16 doorframes and one ceiling(all stone). Make a 2x2 with the stone doorframes 2 high. Lure the manta through a empty space and then place your last 2 doorframes. You can then place your ceiling and laydown on it to feed angler gel for tamming. You might need a few extra doorframes to keep it from moving.Good luck these things are savages. -Legend
They have terrible turning circle, approach one from above and feed it. Then let it swim circles around you. The occasional time it gets close you can predict its attacks, it “bucks” just before the attack, which is the tail swinging underneath. Quick swim up or back avoids it. Be prepared to get dizzy, long time between feeding
Tame a kaprosuchos and swim to one of these bad boys and do it's alternate attack it will grab it in it's mouth. walk onto the shore where its safe and have another person feed it while in the gators mouth (if you unmount it drops it) it wont attack or die because it's technically not on the shore.