I think this looks like a small Anaconda, with the olive colouring, and water snake head.
Mildly venomous, but harmless to humans.
A back-edged crossbar runs down its olive grey back, eyes bulging near the front and top of its head, and two enlarged teeth at the back of the upper jaw, with which it can envenomate. Sounds like my ex-wife....well, it would if I had an ex wife. I am still very happily married, thank you.
Loves tidal shrimp ponds and Mai Po is one of the very few places that you can see this snake. Can be daytime or nighttime active, and feeds on mudskippers and fish.
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