I was thinking the same way as well the moment I read the title. I've encountered them before but I never had the heart set into keeping it.i figured it was just some fancy trade name for a miscellaneous mormyrid.
Looks like something VERY hard to keep.....
I bet that mouth only eats certain tiny foods....
if it's a true dolphin, that would mean it's a mammal, not a fish.and for what it's worth, i don't think dolphins care too greatly if the water is salty or not.