Johnius is a genus of marine ray-finned fishes belonging to the family Sciaenidae, the drums and croakers.

They are commonly known as croakers due to their ability to produce purring, croaking and knocking sounds.

They have a characteristic hammer-shaped swim bladder with between 12 and 20 pairs of dendritic appendages along its sides.

[3] The largest species as J. dorsalis and J. dussumieri which both have a maximum published total length of 40 cm (16 in).

[8] Johnius croakers are found in the Indo-Pacific region from eastern Africa to Australia and New Guinea.