Goldfish don't belong in fishbowls.
"A bowl really isn't a viable container for a goldfish," says Russell Taylor of Vienna, Va., a longtime goldfish keeper and member of the board of the Goldfish Society of America (www.goldfishsociety.org).
"A goldfish has the potential to grow into a fairly large fish," getting 6 to 8 inches long in a year, Taylor says.
Bowl-dwelling stunts a fish's growth, along with its longevity: a year or two, compared with seven to 10 years in optimal conditions.
Taylor notes that the ever-expanding goldfish needs a good-sized aquarium. He recommends alloting 10 gallons for every fish.
Then there's housekeeping. "Goldfish put out a lot of waste products, such as ammonia, that are very toxic to them," he says. A filter system and frequent water changes are musts.
And a fishbowl just isn't large enough to support enough "good" bacteria to convert waste into less toxic compounds.
Raised by fishkeepers in China since before 1000 A.D., goldfish have "double the amount of genetic material and chromosomes that most fish have," Taylor says.
That explains the species' many mutations, the most basic of which is the gold color; other hues include black, blue, calico and albino.
Among the 20 or so categories of goldfish mutations are eye types, such as celestial eye, which protrudes and looks upward; fin mutations, such as double tail fins; and body shapes, such as the round body.
Price ranges can be just as dramatic. "There's a pretty remarkable spectrum. You can pay 10 cents in a pet store or several hundred dollars from a breeder who specializes in fairly high-end fish," says Taylor, who has never spent more than $30.
Still, even fancy varieties are available at pet stores for a few dollars. But that affordability actually may work against the goldfish.
"If you buy a sufficiently large tank, filter and other necessary equipment, you're going to invest at least $50 for a fish that might cost 50 cents," Taylor says. Given those lopsided economics, "It's hard to push people in the right direction." And the bowl beckons.
Although the hardy goldfish is often described as a good choice for beginners, Taylor doesn't necessarily agree.
"What they have going for them is they are colorful and very responsive to owners. But for the very inexperienced, guppies or corydoras catfish are probably better suited for minimal care."
Not aggressive, goldfish can be good community fish. But "they'll eat anything," Taylor warns, including innocent bystanders small enough to fit in their mouth.
With diet, variety is key. In addition to pelleted or prepared foods, Taylor recommends frozen foods such as bloodworms and brine shrimp, as well as veggies.
He avoids flake foods, many of which he says are "not nutritive." They also pose a problem with some round-body goldfish, which can gulp air at the surface and develop floating problems.
Although goldfish have a reputation for needing less oxygen than other fish _ another reason they are relegated to bowls _ that just isn't true.
"Particularly the fancier varieties can be very sensitive to available oxygen in the water," Taylor says. "You see that in ponds that are heavy with algae. At night, the algae uses oxygen, and you'll see the goldfish hanging at the surface and gulping pretty hard."