Aquatronian

Aquatronians are a subspecies of Cybertronians from the ocean planet Aquatron, which lies somewhere in the Orion Arm of the Milky Galaxy.

Anatomy
Aquatronians share a similar biology to other Cybertronians, though they generally transform into robotic fish and assort sea like.

Culture and society
The Aquatronians founded massive automated Energon refineries all across the seabed, maintained by robotic organisms such as the Cleaners. Their uniquely oxygenated mixture of Energon is cheap to produce and extremely efficient.

Unlike many of the other lost colonies left isolated after the collapse of the space bridges, Aquatron was eventually found, though not by Cybertronians. Rather, they were found by Quintessons, who annexed the defenseless little world into their Imperium and repurposed the resident Sharkticons into an army to quell any potential rebellions.

To outside observers, the brutally subjugated Aquatronians appear to be happy and productive Energon traders under the benevolent guidance of the Quintessons' Co-Prosperity Sphere. But dig a little deeper and the Quintessons' web of lies will swiftly unravel.