Mullet
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. Mullets have served as an important source of food in Mediterranean Europe since Roman times. The family includes about 78 species in 20 genera.
Mullets are distinguished by the presence of two separate dorsal fins, small triangular mouths, and the absence of a lateral line organ. They feed on detritus, and most species have unusually muscular stomachs and a complex pharynx to help in digestion. While its facade is all business, it has been known to have a party or two in the back.
A common noticeable behavior 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 hypothesized to be in order to gain oxygen rich air for gas exchange in a small organ above the pharynx.
By Ray eye (selbst fotografiert von Ray eye). CC BY-SA 2.5, via Wikimedia Commons
By Roberto Pillon. CC BY 3.0, via Wikimedia Commons