Mammoth Rider - Aquatic Options?

[Buzzcop]

Hello fellow pathfinders, I am currently DMing a Skull and Shackles campaign and the party is nearing level 10. One of the players, a cavalier, has expressed interest in the Mammoth Rider prestige class, but with an aquatic mount. He is currently riding a modified swordfish that he and I brewed up together, but not sure what animal would be an appropriate / balanced huge aquatic companion if he does decide to try that route. Anyone have some advice on which creatures would lend themselves to such a sweet killer concept, or should would simply "bulking up" his swordfish to huge size be the way to go? Thanks in advance!

[HaraldKlak]

Assuming the current sword fish is large, I'd just bump that up to huge, and add the bonusses granted by the prestige class.

Mammoth Rider is quite easy to adapt to other animal choices given that, you don't have to recalculate the existing statistics but just add what the class says at a given level.

[Glutton]

Giant water lizards like Elasmo's, Orcas, Sharks, Emperor Walrus, Giant manta ray

[haruhiko88]

Ride the walrus! Although I have used an orca with a cavalier before and it was awesome. Blind sight out to 120ft was amazing to have minus the whole dm said it doesn't work out of water. But there was the one time it gained the celestial template, gm gave it wings and for 1 glorious session it was the good year whale... I miss my cavalier. Ooh one other mount is the Sea Snake, that could be fun.

[The Beard]

You must ride the kraken into battle.