I saw a mudskipper, a shell moving, and a katang. All within the radius of a small mangrove tree.
The cone-shaped shell is traversing a dead branch or root of the mangrove. A new shell, white, irregular shape is patiently walking under water then rests near an are on the bank and then moves again. This is a hermit crab.
A big adult mudskipper golden brown with a black line and silver underskin was swimming carelessly when it sensed me. It latched in a dead branch of a cut mangrove. Underneath this same branch, a small black katang also clings. When it felt that I moved after being impatient, it swam to a farther mangrove.
Two chestnut munia on the railroad.