The green penpoint gunnel comes in various shades of green or brown. It is commonly seen up to20 cm long, though it can reach up to 45 cm in length. You can recognize this little one by the dark bar below each eye.
There is a row of dark spots along the central body and a number of short, bar-like markings extending down from the top of the dorsal fin. The tail has slightly longer rays to it and the anal fin is about half the length of the dorsal fin.
The green penpoint gunnel can be found along the shoreline areas of the pacific northwest coast, usually in the shallows. It can sometimes even be found in tidal pools, or look in eelgrass beds, sea lettuce beds, or in stands of kelp. It will take on the color of the vegetation around it. In the winter, when there are few plants, it will hide under rocks and in crevasses, it can breathe air when it is out of the water and can remain out of the water as long as it stays wet. During the warmer months when plant life is in abundance, they will be a green color.
Spawning happens from January to March. After laying the eggs, one or both parents will coil around the egg mass to protect it. The incubation period is up to 2.5 months. The newly hatched larvae average about 12 mm in length, and their body is transparent.
There are three color phases of these fish. These phases are partly the result of their feed, there is a green phase, a brown phase, and a red phase. The larvae do not begin to get color until they settle to the bottom and begin to feed. Green penpoint gunnels feed on small crustaceans and mollusks.