[T]he whole plant, instead of rising to the surface of the water as hitherto, hung limp from the fissure where it was placed, and trailed upon the sand. Coincidently, (was it consequently?) a greenish tinge pervaded the water, speedily increasing in depth and opacity. In five days, no object could be discerned six inches from the glass, and my beautiful Aquarium was transformed to an unsightly ditch.

— “My Aquarium,” The Atlantic, 1858

For as long as man has tried to keep an aquarium, he’s been struggling to keep it clean. This unavoidable aspect of the hobby was immediately evident on entering the 21st Annual Marine Aquarium Conference of North America in Atlantic City, New Jersey. Put another way, don’t go to a marine aquarium conference expecting a kind of bustling World’s Fair of tanks and fish and crabs and shrimps and snails and undulating seaweed. You’re only setting yourself up for disappointment.

Of course if that’s what you expected, then MACNA XXI wasn’t probably for you in the first place. If, however, you maintain a marine (or saltwater) aquarium, then MANCA is like Christmas in September: an annual celebration when you can be excused for throwing financial caution to the wind and coming home with halide lights and calcium reactors and computerized aquaculture monitors.

Such gadgets are what make the hobby possible. At first glance an aquarium looks like a tiny piece of the ocean brought into the home — a slice of the natural world transported to a rec room or a pediatrician’s office or a restaurant bar. But the creation of such a naturalistic scene is a highly mechanical process.

This is not a recent development. The keeping of fish and other water creatures is itself a millennia-old practice, the sea long being one of the planet’s most inaccessible and therefore fascinating (and often frightening) environments. The Greeks and Romans maintained fresh- and saltwater ponds. Around the 10th century, the Chinese began keeping goldfish as pets — a practice that spread to Japan and in the 16th century to Europe and, two centuries later, to the United States.

Creating saltwater aquaria proved trickier. Of course anyone could throw some marine fish and invertebrates into a glass tank; keeping them alive was a different story. A 10-year-old today can buy a cheap electric water filter, affix it to the back of a tank, and watch as water is drawn in, pulled through a white-fiber and cotton filter, and gently, pleasingly trickled back out onto the water surface. Thanks, Anna Thynne! She’s the British marine zoologist who in 1846 discovered that transferring water between canisters for 45 minutes oxygenated the water sufficiently to keep her corals alive. A few years later, London chemist Robert Warington discovered that the right combination of oxygen-producing plants and oxygen-consuming animals could create a self-sustaining system. Philip Henry Gosse came up with the term we use today, publishing The Aquarium: An Unveiling of the Wonders of the Deep Sea in 1854 and kicking off the British aquarium fad among Victorians, fish and crabs joining canaries and ferns and shells in the living rooms of those 19th-century obsessors for anything natural.

Not that its unnaturalness went unnoticed. Writing in the American Naturalist in 1876, aquarium supply dealer William Alford Lloyd noted the hobby’s inherently technological nature. “Aquarium work, being hydraulic engineering on a small scale, is essentially the work of an engineer and not that of an architect,” Lloyd wrote, “unless he is also an engineer and a mathematician.” Industrial innovations including the increasing affordability of glass, the development of artificial saltwater, and transportation innovations that made the shipment of marine organisms across greater distances meant that over the next century, aquariums moved into more and more homes, further and further inland.

At MACNA, these engineering tools included light fixtures and de-ionizers and pumps and skimmers and wave machines and chemicals to cure fungus, ulcers, milky skin, raised scales, fin rot, tail rot, mouth rot, and bulging eyes. Any romantic notion of the sea and the life contained within was unapparent here in the windowless main hall of the Atlantic City Convention Center. I watched, for example, a presentation on light levels from a professor of industrial and manufacturing engineering. He used graphs of spectral irradianance (watts/m^2/nm) vs. wavelength (nm) to help explain the process of collecting light data.

If marine aquarium hobbyists are not outwardly romantic, they are unabashedly passionate. In an article in the latest Reef Hobbyist Magazine entitled “Preparing to Leave Your Tank”, a writer laments that, sigh, there are times when aquarist and aquarium will be separated as “summer vacations and holiday excursions with family are, for many, a necessary part of life.”

Many would indeed like to turn their hobby into a living, which isn’t as easy as it may initially seem to the saltwater enthusiast. The competition is stiff. Overhead is high. In a talk on how to find your professional way, Steven Pro — a 15-year vet of the ornamental aquatics industry, as the field is called — had a word of warning for those in the audience who thought, Oh wouldn’t it be nice to open an ornamental aquatics retail store. “I’ve seen a ton of guys lose their jobs in IT and open a store,” he said. “Whenever I see one, I think Dead Man Walking. I can see three years into the future and he’s divorced and lost his house.”

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It’s a big business, to be sure. According to the United Nations, an estimated 1.5 to two million people maintain saltwater aquaria around the world; the trade in fish and coral and invertebrates is anywhere from a $200 to $330 million industry.

But wait, you may be saying: Why is the United Nations keep statistics on a hobby? These are clown fish, not blood diamonds, you think.

True. But the the keeping of marine plants and animals has surprisingly strong social and environmental consequences. In a 2003 survey — From Ocean to Aquarium: The Global Trade in Marine Ornamentals — the United Nations Environment Program’s World Conservation Monitoring Center found that 20 million tropical fish representing 1,471 species are harvested for aquaria every year, largely from Southeast Asia for buyers in Europe and the United States; 12 million corals, and nine to 10 million crustaceans and mollusks come out of the seas each year, too. The trade provides much-needed jobs in poor nations: In Sri Lanka, the industry involves 50,000 people and annual revenues of $5.6 million. But unsustainable harvesting — both in terms of the number of animals captured and the way in which they’re obtained — can threaten the fragile but ecologically important coral reefs as well as the much-needed source of income for these struggling nations. In many Southeast Asian countries, for example, collectors use squirt bottles filled with a cyanide mixture, which they shoot into reef crevices. The chemical stuns fish, making their capture easier, but it also damages the reef and can potentially kill the fish, necessitating the capture of even greater numbers.

The theme of conservation ran through the Atlantic City show. Among the few living things sold at MACNA were small fragments of coral, or “frags.” You know how a spider plant puts out those babies that you can cut and put in a glass of water? The creation of frags is a similar process (though a bit more complicated). Generally, small polyps are cut from a larger coral colony and attached to a rock using rubber bands or glue. The process helps reduce the demand for wild-harvested coral. At the show, dealers like Artisan Coral and Mr. Coral had wide, shallow tanks filled with rows of frags under UV lights. The light highlighted the Day-Glo reds and yellows and greens of the tiny corals; most dealers would hold a purchased frag for the buyer until the three-day show’s end, though some attendees come with their own tanks that they set up back in their hotel rooms.

All this time and money, technical equipment and technical know-how, to make an aquarium, to gain the privilege of viewing an idealized scene of nature in the comfort of one’s home. “I could spend the day in showing you my Aquarium;—the merry antics of the blithe Minnows; the slow wheeling of the less vivacious Sticklebacks; the beautiful siphon of the Quahaug and the Clam,” wrote that anonymous Atlantic author back in 1858, describing the tank after weeks-long efforts restored the microcosm to its crystal glory. The aquarium is in many ways like lush Hudson River paintings, or National Park vistas, or botanical gardens — created or conserved or contextualized, they’re all manufactured tableux of the natural world. Humans are marginalized in these scenes, welcome to look on but as detached observers. Intruders, not integral parts. The overtly technical nature of the aquarium may make it seem at first glance as the weakest of these types, then. With its exposed pump systems and artificial lights and faux wood finishes, it is the most honest about its humans origins and could therefore seem the least effective celebration of the natural world. Yet that element is also an overt symbol of just how difficult it is to make even a 20-gallon facsimile of the environment. Water in the tropics is a luminous blue, but water at home can turn cloudy in a day. Sunlight makes those warm water seas sparkle, but at home it can give you a thick sheet of algae. Maybe the best tribute to nature is an honest acknowledgment of just how difficult it is to recreate it.

Not that the marine aquarium community seems likely to stop trying anytime soon. Among the dealers on the trade show floor was a booth for MACNA XXII, which will be held in Orlando, Florida in 2010. Representatives for that show passed out mouse-ear hats and gave visitors press-on temporary tattoos. For the rest of the show, attendees walked up and down aisles with palm trees on their cheeks and necks, already excited for next year’s pumps and filters and long ultraviolet light bulbs before this year’s had even sold out. • 5 October 2009