CRITTER: Meet the rare Thompson’s Anthias Fish from Ni’ihau

I have been scuba diving all around the world for the last 20 years shooting marine life videos for a school educational program and my goal is to get video of the rarest fish species in the sea and study their behavior. It was really wonderful to find one of these rarely seen creatures right in my own backyard!

The island of Ni’ihau off the coast of Kaua‘i is a spectacular dive site with 400 tall feet underwater cliffs, huge rock arches and underwater caves. Because Ni‘ihau is out in the middle of the sea and surrounded by deep water it has many marine life species you can’t find anywhere else. You can dive with a humpback whale, monk seal, manta ray, sandbar sharks and clouds of butterfly-fish all at the same time! What is also very unique about diving at Ni‘ihau is the rare and unusual critters that live on these steep underwater cliffs and in the caves that are over 100 feet deep.

The dive company I went on my last trip to Ni‘ihau with knew that I was trying to document some of the rare Hawaiian fish species and they told me they had found one of them recently called the Thompson’s anthias. This fish is about 8 inches long and is bright orange with purple lips and green eyes! I had seen pictures of this fish that were taken in the Northwest Hawaiian Islands but had never seen one anywhere in the main Hawaiian Islands. I jumped at the opportunity to look for these strange and beautiful fish.

When we got to the dive site which takes over an hour of rough water boating from Kaua‘i to get there, we moored just off of Lehua next to Ni‘ihau. I asked the dive master where he had seen the anthias at and he said straight down off the underwater cliff at about 120 feet deep! Those of you who scuba dive know that diving down deeper than 100 feet is risky and not recommended due to the possibility of having negative effects from nitrogen build up in your blood, but he knew I had done thousands of scuba dives so we were safe to go look for the fish.

I turned on my movie camera and bright video lights and we jumped in the water and started to sink down this steep dark cliff. At about 110 feet deep the dive master pointed to a crack in the reef and I knew he was telling me where he had seen the pair of Thompson’s anthias on a recent dive. When you scuba dive down to 120 feet deep you can only stay there for about five minutes and be safe, so I had one chance to find these fish. All by myself surrounded by large sharks and clouds of butterfly-fish I looked into the crack and, sure enough, the anthias were there, and I got a beautiful video clip of them!

Anthias fish are more common in other parts of the Pacific where they can be studied safely at depths of 40 to 50 feet, but here in Hawai‘i they are super rare and normally live so deep we know very little about them and they may even be new unknown species around Ni‘ihau. From time to time these fish breed and produce a large amount of offspring, and the divers see them on a regular basis, then they just all seem to disappear and no one sees any for years at a time. We still know so little about the sea around us and the amazing creatures that live there. As far as we know the anthias do not have a Hawaiian name because living in such deep water the Hawaiians more than likely never saw one!

You can see the Thompson’s anthias in action on my marine life educational web page at www.underwater2web.com in my movie “The World’s Guide To Hawaiian Reef Fish,” and also sign up on my YouTube Channel at Underwater2web and get a new and exciting marine life movie every week!

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Terry Lilley is a marine biologist living in Hanalei. He is co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to www.reefguardianshawaii.org.