- Kingdom: Animalia
- Phylum: Echinodermata
- Subphylum: Asterozoa
- Class: Asteroidea
- Order: Forcipulatida
- Family: Asteriidae
- Scientific name: Leptasterias muelleri
- Norwegian: lite korstroll
It can be difficult to distinguish the northern starfish from a juvenile spiny starfish. The most obvious difference is that the spines of the northern starfish are not as orderly orginzed in rows, running along the arms. The common starfish is also very similar, but the spines has has a single point in contrast to the northern starfish, where each spine has a "rose" of usually 4 to 6 points.
Adult individuals are approximately 6 cm across, but might grow significantly bigger. The color is usually green, pink or violet. On small individuals the spines are often organized in lines along the arms. In larger individuals they may be more scattered.
The northern starfish seems to thrive on rocky, exposed locations as well sheltered, muddy sites. It can be seen from the tidal zone and down to 200 meters.
It is widespread on both sides of the North Atlantic Ocean.