Sledfish (Patreon)

Spitballing some aquatic beasts of burden. Much like horses, in current-era scud planet raising sledfish and using them to pull cargo is a niche hobby. Chariot-style races are a fairly popular competitive sport though. Up and down movement is controlled by pulling on the flexible rods above and below the team, and side to side movement is either controlled by vocal queues or electromagnetic emitters on either side of the harness.

Sledfish are enthothermic air-breathers, like porpoises, which is makes them a much faster, smarter, and higher endurance creature than most open-water swimmers of comparable size. It does mean that the sled drivers have to take care to make sure their animals can breathe when they need to though.

The whiskers are shorter in wild sledfish, scuds selectively bred for them because they consider their resemblance to antennae charming.