Whether we realize it or not, the fishes in Hawaii (and elsewhere, world-wide) are quite remarkable. The Trumpet fish definitely not an exception …. It is actually quite an amazing species when you know the facts.
The Trumpet fish is known locally as the “nunu” and can be spotted in caves, lying under ledges, and in both shallow and deep waters (up to about 100 meters or 328 feet). Sometimes it was bright yellow, other times it had a dark coloration. It is generally long and thin (much like the Needle fish or Cornet fish, both in the same family) but easily distinguished by the complex shape of its head.
They’ve adopted a few pretty ingenious hunting strategies to get what they want; their prey is usually reef fish or shrimp. They might hang motionless in the water, in sync with the wave action, and then lunge forward, inflating their trumpet-like mouth and vacuuming up their meal. It’s not surprising to see one sneak alongside a school of grazing Surgeon fishes to get within striking distance. Another tactic is to hover vertically against the backdrop of branching coral.
They can also change their coloration from grayish to yellow, or an orange-brown. The dorsal and anal fins are set back towards the tail, and small movements of these fins can propel it forward and back. Distinguishing features of the trumpet fish include a fan-shaped tail (called a “caudal”) fin and a chin (called a barbell).
They are closely related to tangs and surgeonfish and can grow to about 20-24 inches in length, though their skin is smooth and less susceptible to skin diseases than that of other tangs. They prefer water temperatures of degrees 75-79 fahrenheit.
The horn-like appendage between their eyes begins growing when a young fish reaches about 5 inches in length and tends to be a little bigger on males. Unicorn fish are generally not aggressive to each other, but when they do fight they use sharp scalpels by their tails as weapons, not their horns.