When taming this, be careful, Mantas and sharks follows a basilosaurus around and will attack you if you approach or feed the basilosaurus. According to the Basilosaurus dossier, Mantas usually follow them because of their eating habits (Well very messy) and it leaves plenty of leftovers for them. They attack you when you feed a basilosaurus because it leaves no leftovers for them.
I believe the dossier, but yeah.
Click the arrow pointing to the sky if useful, thanks 😊 (Sorry for the dossier spoiler)