If caught in open water by a manta fight don't flee. If you have a spear or pike swim up as it gets close. This keeps you above it attack area and puts you in striking range. The manta is slower moving up and down in the water.
The manta is quite dangerous, as it's attacks can punch straight through armour, even flak. They are very fast and unless you have lots of oxygen and speed, you will not escape. Just poke your head underwater and look left and right before crossing the sea. It's like a road, but worse, because roads don't have angry stingrays, very large sharks and/or killer piranha
Taking it is actually pretty easy,just ride on your pelagornis and slowly start feeding it angler gell(which can be found in snails on mobile)make sure it’s near shore and away from predators!(like other mantas)its a passive tame so make sure not to get killed in the process
Mantas are very quick ocean transport mounts, which also double as a powerful PVP asset. The manta's attack ignore the armour stat, which makes a high melee damage manta incredibly powerful to players and small tames. It's quick speed also allows it to move very fast. It can jump out of the water, but on contact with land, it will begin dying very fast. Very good for travel on the center map, as it can jump over the many islands if it gets a good run up
Surprisingly in mobile ark, if you attack achatinas with raptors, as I have learned from my own experience, you can get angler gel. I have never gone past the shallows in the ocean, yet I have multiple stacks of angler jell. Hope y’all can find this helpful. Don’t know if it works on other versions of ark though.