Fish crowd Hua Hin shoreline after water changes; cause still unconfirmed

What has changed

Fish gathered unusually close to the shore at Hua Hin and Khao Takiab on Sunday, 25 October, as coastal water turned murky red, according to local reports. The precise cause has not been established in the reporting reviewed for this update.

Hua Hin Today’s 26 October account and MGR Online’s original report describe residents and fishermen using nets and other equipment to catch fish in the shallows. Some small fishing boats also operated close to shore.

What was observed

The reports identify several kinds of fish among the catches, including grouper, sole and sea catfish. Residents took catches home, while larger quantities were partly sold or preserved. That describes what people did; it is not an official finding about whether the catch was suitable to eat.

The local term used for the conditions is nam biat. MGR Online says the exact reason for the discolouration and gathering of fish requires investigation by the relevant agencies.

Why fish can gather in shallow water

In an explanation published in September 2017 about an earlier Hua Hin event, the Department of Marine and Coastal Resources describes freshwater meeting seawater and forming layers that mix slowly. Oxygen can decline in the lower water, stressing marine life.

The department also explains how wind and water discoloured by plankton can contribute to low-oxygen conditions. Fish may move towards boundaries between water masses, the surface or shallower areas to escape.

That official explanation provides background to the term. It is not a laboratory result or diagnosis of the October 2026 episode, and the colour of the sea alone cannot establish which process occurred.

What visitors should take from the reports

This account concerns observations on 25 October. It does not establish that the same conditions persist everywhere on 27 October, or that the sea has since returned to normal.

Before swimming or taking part in water activities, check current local notices and conditions at the specific beach. Neither the reported catches nor an attractive-looking stretch of water should be treated as an official assurance about water quality or seafood safety.