Merperson

The Merpeople are a telepathic race of aquatic fish people that were once slaves of the Y'Lyntians in TMNT.

Physiology
They were mutated humans transformed by the Crystal Sun. They were amphibious capable of operating on both land and sea. They possess telepathic abilities which enables them to communicate. In the TMNT (2003) Series, it shows that the Merpeople have long lifespans.

History
The Merpeople were once humans that were mutated by the Crystal Sun, to bring the Y'Lyntian's the bounty of the sea.

After a revolt and the Fall of Y'Lyntius, the surviving Merpeople were free and spread across the seas. They eventually managed to reach a pristine uninhabited North America. However, over the years, humans began to encroach on their territory, forcing them to hide themselves. They began to die out due to human pollution, until only five remained (four males and one female). But there may be hope as the female died protecting her laid eggs.

Source

 * TMNT Vol. 1, #28


 * TMNT Vol. 2, #4
 * TMNT Vol. 2, #5
 * TMNT S03E16 Entity Below (2005)
 * TMNT S04E03 Sons of the Silent Age (2005)