Finally, I got it. This is a mudskipper (Oxudercidae family); called belacak in Malay, tembakul in Indonesian, and ticak bakoy in our native language (Aceh). The mudskipper is an amphibious fish that can survive in and out of water for a long time. The habitats of mudskippers are distributed in muddy areas in the mangroves.
It took a sacrifice to capture this guy. I was willing to crawl in the mud. But the result was worth it.
Look at that face! It mimicked a hippo...so cute! The mudskipper moves agilely with fins and occasionally flounders like a fish stranded on land. What a fantastic creature!
