A study of fish on the island of Pulau Redang has revealed a new species of walking catfish.
Ichthyologist Heok Hee Ng, who works in the Fish Division at the University of Michigan's Museum of Zoology, was undertaking an ichthyological survey on the island of Pulau Redang, which lies off the north eastern coast of Peninsular Malaysia, when he discovered what he believed to be Clarias cf. batrachus.
However, further analysis on the catfish revealed that the fish was actually a distinct species from C. batrachus.
The new catfish, which Ng has called Clarias sulcatus, differs from batrachus because the distance between the tip of the occipital process and the dorsal fin base is different, the fontanel is narrower and the snout is broader.
For more details see the paper: Ng, HH (2004) - Clarias sulcatus, a new walking catfish (Teleostei: Clariidae) from Pulau Redang. Ichthyological Exploration of Freshwaters, Vol. 15., No. 4. 289-294.