This 30-inch-long, common Hawaiian reef fish can come in many different colors, and they often hide in large schools of fish so their colors match the species of fish they hide in!
On reefs where there are a lot of yellow tangs (lau‘ipala), the nunu are often bright yellow, and on other reefs where there are a lot of convict tangs (manini), the trumpetfish are often green and brown banded or striped.
These fish are long and skinny, and have little fins so they can move forward or backwards easily. This is because they hunt for small fish that live in cracks in the reef.
They stick their long, thin head into a crack, then open their mouth quickly and suck in fish that are even larger around then they are. Much like a snake, the nunu can expand their mouth to twice the size of their head, and they do it so fast that their prey never knows what just ate them!
The trumpetfish has learned a great way to sneak up on the small fish that dart into the cracks in the reef when a larger predator comes by.
They hide in the middle of a school of algae-eating fish like the convict tangs. Since the tangs don’t eat the smaller reef fish they don’t dart into the cracks when the large school of herbivores goes by, but the nunu hiding in the school will grab them!
Trumpetfish can be confused with the cornetfish, which looks similar but is usually a greenish color and thinner. The cornetfish has a long spike on the end of its tail, whereas the trumpetfish has a rounded tail.
Divers usually enjoy watching these fish hunt, as they usually ignore humans, and the nunu will stand on its head looking strait down at the reef. A small fish in a crack it not likely to see it because it is only looking at the tip of its mouth and not its whole body of the fish if it laid sideways to the reef.
You can see nunu in action up on the underwater educational web page at www.underwater2web.com in the movie “The World’s Guide to Hawaiian Reef Fish,” and also follow the daily marine life educational post on Instagram at terry.lilley.
Aloha from under the surf,
Terry Lilley is a marine biologist and Hanalei resident. His web sites include underwater2web.com and gofundme.com/5urrm4zw.