CRITTER: Meet Ni’ihau’s Rare Thompson Fish Anthias

I’ve been scuba diving all over the world for 20 years, shooting sea life videos for school educational program and my goal is to get videos of the rarest fish species in the sea and d study their behavior. It was truly wonderful to find one of these rarely seen creatures in my own backyard!

Ni’ihau Island off Kaua’i is a spectacular dive site with 400 foot high underwater cliffs, huge rock arches and underwater caves. Because Ni’ihau is in the middle of the sea and surrounded by deep water, it is home to many marine species that you won’t find anywhere else. You can dive with a humpback whale, monk seal, manta ray, gray sharks and swarms of butterflyfish at the same time! What is also very unique about diving in Ni’ihau are the rare and unusual creatures that live on these steep underwater cliffs and in caves over 100 feet deep.

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

When we arrived at the dive site which takes over an hour of rough water sailing from Kaua’i to get there, we docked just off Lehua next to Ni’ihau. I asked the dive master where he saw the anthias and he told me straight down the underwater cliff about 120 feet deep! Those of you who dive know that diving deeper than 100 feet is risky and inadvisable due to the possibility of negative effects from blood nitrogen buildup, but he knew that I had done thousands of dives so we were safe to get the fish.

I turned on my camera and some bright video lights and we jumped in the water and started sinking down this steep dark cliff. About 110 feet down 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 dive 120 feet deep, you can only stay there for about five minutes and be safe, so I was lucky to find these fish. All alone surrounded by large sharks and swarms of butterflyfish, I looked into the crack and sure enough the anthias were there, and I got a wonderful video clip of them!

Anthias fish are more common in other parts of the Pacific where they can be safely studied at depths of 40 to 50 feet, but here in Hawai’i they are super rare and normally live so deep that we know of them. very little about them and they may even be new species unknown around Ni’ihau. Once in a while these fish spawn and produce a large amount of offspring, and divers see them regularly, then they all seem to disappear and no one sees them for years. We still know so little about the sea around us and the amazing creatures that live there. As far as we know, anthias don’t have a Hawaiian name because living in such deep waters, Hawaiians have probably never seen them!

You can see Thompson’s Anthias in action on my educational marine life webpage at www.underwater2web.com in my movie “The World’s Guide To Hawaiian Reef Fish”, and also subscribe to 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 non-profit organization whose mission is to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai’i, go to www.reefguardianshawaii.org.

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