The mullets or grey mullets are a family (Mugilidae) of ray-finned fish found worldwide in coastal temperate and tropical waters, and some species in fresh water Wikipedia
A common noticeable behaviour in mullet is the tendency to leap out of the water. There are two distinguishable types of leaps: a straight, clean slice out of the water to escape predators and a slower, lower jump while turning to its side that results in a larger, more distinguishable, splash. The reasons for this lower jump are disputed, but have been hypothesised to be in order to gain oxygen rich air for gas exchange in a small organ above the pharynx Wikipedia
Location: Sungei Buloh Wetland Reserve – Jan 2023