Oh, I just saw the tapered tale, I bet it is a paddy eel, Monopterus albus, they are found all over asia and in Hawaii, They range from 40-100 cm. depending on where they are from, and are very hardy, surviving in brackish to full fresh, mountain streams to stagnant ponds, and tropic heat to mud under ice. A common food fish. here is a market photo by Zhou hang.