Nerophis ophidion

The Straightnose pipefish has a greenish-brown colour, with black and white notches on the head. This pipefish is known for its strong sexual dimorphism. Females are larger than males, and show blue-coloured stripes on the anterior part of the body together with a ventral skin fold. These characters, signaling higher reproductive capacity, are used by males to choose the best female. 

This species breeds between April and October, with males having multiple pregnancies within a single breeding season, each from a single female. Females display themselves above the eelgrass, competing with other females without aggressive interactions. Males signalizing their willingness to reproduce by displaying a snout tip with a yellow tone. When they detect a female of their interest, they engage in a courtship ritual, pairing closer with the female, and going up and down the eelgrass, until egg transfer occurs. The female fills the male’s brooding surface with her eggs and leaves.