Saw that others had luck keeping him around using tames to make him curious, so I tried to tame one of those guys with a pet Spino in tow. Unlike the first time I saw one, it wasn't curious about us AT ALL. It immediately retreated. So, because I'd found it in a river, I tried to corner it.
It committed suicide-by-beach. Literally swam up onto shore and insta-died rather than be near us.
I don't think they like Spinos. Leave yours at home.
Best for killing scorpions on bottom of ocean floor since they don't take torpor. Scorpions down there will knock any other animals out. Once you kill it, hit it with a pickaxe to gather black pearls. Very useful for the next update with tek gear.
Since there's no way to post it on the actual creatures wall I think I should warn everyone whilst taming these beautiful ichthyosaurus watch out and I mean watch out for any Cnidaria jellyfish they will shock you to oblivion I was caught taming when 4 of these guys jumped me and I absolutely freaked out
So yeah Cnidaria are easy to kill but keep your distance!