For the past thousand years native Hawaiians hunted fish using spears in shallow water.
They caught fish for food, medicine and for cultural practices and they named the fish dependent on its behavior, color or connection to life on land. Some fish species like the frogfish never received a Hawaiian name because no one more than likely ever saw one.
Looking down on the reef, a frogfish looks just like a rock and it rarely moves and even modern day divers with snorkel masks pass right over frogfish without seeing them. Many times while diving, I will point out a frogfish on the reef to a tourist diver, and then when we come in they say “what were you pointing at as I only saw a rock”.
Frogfish come in many colors and they can change color to match their background, but what makes them almost invisible is their ability to use their fins as legs. They hold onto the reef or a coral with fins that have little toes and when they move they slowly walk.
Seeing a frogfish move is very rare and they move so slowly they aren’t usually noticed by divers or predators. When a frogfish does move it is usually feeding and that happens so fast you can hardly see it.
Frogfish have a little modified fin on their head that looks like a fishing rod with a little fleshy lure on the end. They wiggle the lure in front of their upturned mouth that can expand to 10 times its normal size and when a fish comes by to investigate the lure the frogfish gulps it in so fast the prey never knew what happened.
Frogfish are the slowest moving fish on our reef when they walk, but when they feed they are the fastest moving fish as it only takes 6 milliseconds to swallow a fish that is almost as big as the frogfish that is eating it.
I once had a fellow diver come in and say they saw something really weird. They said they were watching a small colorful reef fish cruising along the reef then it just disappeared out of nowhere.
It was there one second, and then totally gone the next. I asked him if he could take me to the part of the reef where he saw the fish vanish, and sure enough on our next dive I showed him a large brown frogfish that looked just like a rock.
Frogfish can swim, but they only do so when they have to move from one reef to the next over the sand. The way they swim is totally unique to marine fish as they don’t use their fins to propel forward.
They move through the water by using jet propulsion. They gulp down water with their large mouth, and then squirt the water out of tubes on their flippers causing them to move slowly forward. They steer with their fins that are thrust out like little airplane wings and they look like a very slow moving cargo airplane underwater.
There is nothing normal about a frogfish, and I just wonder what the Hawaiian name would have been given to them if the Hawaiians had seen them many years ago.
One of the best places to see frogfish in Hawai‘i is Koloa Landing in Kaua‘i, but you need to have a local guide find them for you. Most divers will swim right by them and never know they even exist.
You can see the frogfish in action in my Koloa Landing Marine Life Movie up on my YouTube at https://www.youtube.com/watch?v=b3-byBjsz88.
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Terry Lilley is a marine biologist living in Hanalei Kaua‘i and 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 Hawaii go to www.reefguardianshawaii.org.
