By far best dino to tame for deep sea exploration and farming. He's incredibly fast on land, out running taptors, carnos, theriz, etc. His swim speed in water is just as good, with megalodons crumpling to his stun and bite. Great stamina and offense, and you can stay away from base for days with this helpful guy.
1: Do not fight them in water under any circumstances
2: Lure them on to land
3: Use a bola
4: Attempt to Tranquilse with bow and arrow or better
Remember: They can only be tamed with fish meat and they usually kill all the fish in the area so you should probably have some prepared beforehand.