This thing has no equal on speed in the water, just be very careful after investing points into it since the lag can cause some things to appear right when you are on top of them. Also they are very squishy so a pack of jelly fish will usually spell the end for it if you get caught.
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.