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Issue: May 2007

The Aquarium Hobby in Hawai‘i: An Update 39 Years Later

Author: Glenn Y. Takeshita

TAKE T 0507
Photographer: Glenn Y. Takeshita
A veteran livebearer expert who first reported on the fishkeeping hobby in Hawai'i in the late 1960s gives an up-to-date perspective on the changes that have occurred over the years.

It was almost 39 years ago, in the June 1968 issue of TFH, that my first article, “The Hobby in Hawai‘i” appeared. The generous comments in the Editor’s note made this then-budding writer exceptionally proud. In fact, my ego was so inflated that my wife thought my head was going to burst. That passed, but I still have the desire to write that those comments created way back then. Not only have I continued to write articles about fish, but I am putting the finishing touches on a book about Hawai‘i’s potable water.

Hawai‘i is still the land of swaying palm trees and hula girls, and it also a tropical fish hobbyist’s paradise, despite dramatic changes in Hawai‘i and in the fish hobby. The aloha spirit and Hawai‘ian hospitality remain our greatest assets. There has been tremendous growth and development in Hawai‘i. The population on the island of O‘ahu has grown to over a million people, and the other islands of the state have seen similar growth. And, of course, thousands upon thousands of tourists from the Orient, Europe, and the continental United States come each year to enjoy the islands. As anywhere, this growth has had bad consequences, but overall, we’re still a paradise!


First let me update you about our state’s water supply—a most important subject when it comes to our beloved hobby. I recently retired from the Honolulu Board of Water Supply, where I worked for 35 years, reaching the level of Assistant Chief Chemist. I still consider Hawai‘i’s potable water—especially on the island of O‘ahu—as one of the best water supplies in the world. In Honolulu the primary source of potable water is still artesian well water. We do still have some perched (tunnel) water in windward O‘ahu, but we do not use any surface water sources. Back in 1968 we had 52 sources to supply O‘ahu’s water, but today we have more than 180 sources.

Chemical Parameters

In the last 39 years the quality of O‘ahu’s water has changed significantly. The dissolved mineral level has increased in most sources because the freshwater lenses are decreasing in size and brackish transition water is entering the freshwater zone. Also, in most areas of O‘ahu, the water supply provides a mixture from several sources, not one, and this can make it difficult for an aquarist, since the chemistry of the tap water is always changing. This is a potential problem, especially if you are trying to breed fishes that require a specific type of water. The following table indicates the ranges of some parameters important to fish keeping.

Variability of Tap Water Chemistry

Alkalinity 16 to 130 ppm as CaCO3

Total Hardness   22 to 276 ppm as CaCO3

Chlorides 14 to 260 ppm

pH   6.80 to 8.50

Total Dissolved Solids 90 to 737 ppm

Specific Conductance   135 to 1106 μS/cm


The most significant change affecting the tropical fish hobbyist is the chlorination of O‘ahu’s water supply. In 1968 only 20 percent of the supply was chlorinated, but today 90 percent is. This means we have to be careful to add a conditioner to remove the chlorine when making large water changes.


In 1968 there were no organic contaminants found in O‘ahu’s water supply, but now organic pesticides are found in some of the water sources, mostly in central O‘ahu, where pineapple and sugar cane were cultivated. Fortunately, these sources are being treated with granular activated carbon filters. This completely removes the pesticides, so the water is very safe for fish.

Some household water supplies have high copper concentrations from copper transmission mains and from copper household plumbing. This is not a problem unique to O‘ahu, and any hobbyist anywhere who lives in a new home with copper pipes would do well to test the water for copper. This is especially important in soft water areas. Various water conditioners are available from your local aquarium store that will remove copper and other heavy metals if needed.

Outdoor Fish

Almost all hobbyists on O‘ahu keep their tropical fish outdoors in setups ranging from a few aquariums and washing machine liners to elaborate outdoor hatcheries with several hundred tanks, tubs, and concrete ponds. Such outdoor setups are possible because the air temperature on O‘ahu never goes below 60° or above 90°F.

Of course, this makes Hawai‘i a perfect place for commercial fish farming. In 1968 there were no commercial tropical fish breeding operations on O‘ahu, but today, because of a Seagrant project, ornamental tropical fish farms are present not only on O‘ahu, but also on the islands of Hawai‘i, Kaua‘i, Maui, and Moloka‘i. So far these farms are small compared to those in Florida or in the Far East, but production is increasing, and we are trying to create a specific niche in the tropical fish farming industry.

On the other hand, marine aquaculture is already in high gear in Hawai‘i. Saltwater food fish projects have been very successful in the production of mahimahi Coryphaena hippurus, striped mullet Mugil cephalus, and Pacific threadfin or moi Polydactylus sexfilis. Seaweed production—ogo and spirulina—has been successful on Moloka‘i, O‘ahu, and Hawai‘i. There are ongoing projects producing oysters, clams, abalone, shrimps, prawns, and lobsters.

In addition, great strides have been made in breeding and raising ornamental saltwater fish like butterflies, dwarf angels, and clownfish, as well as ornamental shrimps for the aquarium. Freshwater aquaculture has been successful with sunfish (a tilapia hybrid), sturgeon, Chinese catfish, grass carp, channel catfish, and trout. Some organizations are shrimp for broodstock export and microalgae for the health food industry. One of the most ambitious marine aquaculture projects being taken is the offshore farming of moi in large cages in the waters off the ‘Ewa district. These operations involve state and federal government agencies as well as many private companies. There are many professionals in these organizations who are considered giants in their respective specialties. The research they perform often has direct implications for us as hobbyists.

One of these many participants in aquaculture is the Waikīkī Aquarium. While very small for a public aquarium, it has many one-of-a-kind exhibits. The aquarium is recognized worldwide for many of its undertakings, including the coral propagation project.

An Unfortunate Decline

In 1968 there were five tropical fish clubs in Hawai‘i, but today there are only four. The Hawai‘i Guppy Association was a very strong organization in 1968, but today it is defunct. I couldn’t believe it when I discovered this during my research for this article, since it had been such a strong club. It is also amazing that there is no marine aquarium club in Hawai‘i!

The Honolulu Aquarium Society, a general tropical fish club, has really grown. They have very informative meetings with guest speakers and interesting and varied programs. They also have an exceptionally exciting monthly auction and a first-class bulletin.

Aquarium Clubs in Hawai‘i Today
Club Membership

Honolulu Aquarium Society    180

Hawai‘i Goldfish and Carp Association    20
Hawai‘i Discus Club    12
Aloha Betta Chapter of the IBC     15
//end table

I was surprised by the current status of the Hawai‘i Goldfish and Carp Association and the Hawai‘i Guppy Association. In 1968 both were strong clubs with more than 100 members. Today one has only 20 members and the other is defunct. It seems as if everyone has joined one big club and the specialty clubs are just not growing.

Pet Shop Irony

In the last 39 years the number of pet shops in Hawai‘i has increased, but today the emphasis is generally on the supplies instead of on the fish. Most stores just sell the staple species—the common, inexpensive varieties. They have a minimal selection of more expensive fish for advanced hobbyists. To get more of these fish, hobbyists have to bring them in themselves from outside sources. Marketing in the pet industry has really changed over the years. I am intrigued and confused by the fact that many pet shops today are struggling to stay open, but at the same time new shops keep opening.

There were about 10 pet shops on O‘ahu in 1968, and there are about 25 shops now. Today many stores focus on dogs and birds, and little attention is given to fish. In 1968 it was the opposite—fish were the main commodity, and dogs, birds, and supplies were supplements. Several shop owners in 1968 were always on the lookout for new fish or the latest new strains and brought them in for advanced hobbyists. Those owners made a lot of money, and their customers got what they wanted, making both parties happy.

Alien Invaders

Streams and reservoirs on O‘ahu are still full of fish, almost all of which are introductions, but there have been a lot of changes since 1968 in what species are found, and where. The five species of indigenous gobies known as o‘opu are endangered, threatened by pollution and habitat destruction. Soon only captive stocks of these gobies may exist.

All other freshwater fishes found in Hawai‘i are introductions, either accidental or deliberate. A partial list of these species is: carp, koi, goldfish, mollies, several species of Gambusia, guppies, swordtails, platies, many African cichlids, four species of tilapia, largemouth bass, smallmouth bass, rainbow trout, channel catfish, bluegills, Cichla, oscars, Chinese snakehead, Chinese catfish, red devils, various plecos, jaguar cichlids, needlefish, threadfin shad, convict cichlids, pacu, several species of Corydoras, and many others.

Most of the freshwater game fishes are found in the Nu‘uanu and Wahiawā reservoirs, but there are some in mountain and drainage streams. Those streams generally have mixed populations of Gambusia, wild and fancy swordtails, domesticated platies, both moon and variatus, guppies, and liberty mollies. In Mānoa stream there are also large populations of plecos, convict cichlids, and smallmouth bass. In Nu‘uanu stream there are many bushynose plecos, smallmouth bass, and tilapia. There is a sizeable population of African cichlids in a stream in Windward O‘ahu. A nearby stream has a well-established population of Corydoras aeneus. During the past 39 years the cichlid Cryptoheros cutteri has disappeared from Ala Naio stream in Honolulu, and Thorichthys meeki has disappeared from Reservoirs 3 and 4 in Nu‘uanu.

In brackish-water inlets, streams, and drainage channels you can find large numbers of sailfin mollies, gray, spotted, and black varieties. In 1968 the Ala Moāna Park drainage channel had a large population of sailfin mollies, but today that population is gone, replaced by liberty mollies, the Cuban endemic Limia vittata, and tilapia. A pond in Salt Lake on O‘ahu is home to a population of sailfin mollies Poecilia latipinna with bothType I and Type II males, the only place on the island that these males can be found.

Trouble in Paradise?

As you can see, many changes related to our beloved hobby have taken place in Hawai‘i during the past 39 years, some good and some bad. Rapid development has disrupted the environment, with a decline of the fishes—both native and introduced—in our streams. Our waters are increasingly polluted by the use of chemicals and by our overzealous expansion and building. In some areas the hobby is thriving, while in others it is declining. We need to turn the tide so that the aquarium hobby once again thrives in this island paradise. I believe I can help with articles like this one. I want the rest of the world to see how the hobby in Hawai‘i has changed. Aquarists here love the hobby and have always made a significant contribution to it. I hope that never changes. Aloha!

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