“Do goldfish grow larger in larger tanks?”
Hell, yeah- goldfish can get really big.
Haven’t you ever heard of Koi? They are really big carp (goldfish) that people put in pool sin their backyard. \
Except, a goldfish, if it is sturdy enough and doesn’t die right away, will grow anyway and so it’s unkind to keep it in a wee little bowl.
Usually they die before the size of the tank is an issue.
I bought an ordinary comet (goldfish) that lived in a bowl, then I transferred it to a tank when it grew large and then it grew to be…maybe eight inches long, with nice flowy fins.
He lived a long time…
Sometimes goldfish can live 30 years or so.
I don’t think so…I’ve heard that this is an aquarium myth (i.e., that aquarium fish grow to fit their tanks). But of course too-large fish will not survive in too-small tanks, so the tank size kind of sets an upper limit in that sense.
How do they KNOW? I’ve heard this before…it astounds me.
What about a goldfish in a kiddie pool? A jacuzzi sized pool? An Olympics size swimming pool? (you knew I was gonna get to that one…)
And also i’ve heard, if you don’t get them a tank-light, they turn white. That true too?
Yes, goldfish do grow larger in larger tanks…because the smaller the tank is, the more likely it is to stunt the fish’s growth. You can control the size of a fish by limiting the size of the tank, but the result of stunting the growth of the fish will be a fish that’s probably very unhealthy. Contrary to the name, goldfish bowls are actually NOT ideal homes for goldfish. The average goldfish would be much better off in at least 10 gallons (that’s right, I said 10 gallons) per fish.
If you want the full story on this issue, check out what some experienced aquarists had to say about the topic on another website :
http://forums.fishindex.com/ubbhtml/Forum1/HTML/000549.html
Carp (goldfish, koi, etc.) release a hormone into the water. When that hormone reaches a certain concentration in the fish’s environment it triggers something in the fish that reduces or stops the animal’s growth.
So if you change the water often enough, you could get the fish so big it fills up the bowl!
Hey, Tapanga - welcome to the Board. Please don’t mind the brusque response you received in the other Forum - it happens to everyone. Happy posting! 
Una
absolutely!
A goldfish is actually just a small carp. In a lake it would grow to full size, but it’s small environment stunts it’s growth!
Ah, the problem of goldfish size may or may not be due to hormones, but it is definitely connected to “waste products”, i.e. poop. The more nitrogen in their water, the slower their growth rate. Goldfish also excrete nitrogen through their gills. So the cleaner you keep their water, by changing it frequently, the more likely it is that they’ll grow really huge. You can keep a goldfish in a 10 gallon tank, and if you do a 25% water change every week like clockwork, he’ll get really big, say about 4 inches long. But that’s only if you do the big frequent water changes.
I once had goldfish in a 1,500 gallon kids’ wading pool down in the basement and they got really huge, like about 12 inches long. But that was because they had, relatively speaking, lots and lots of clean water to swim around in, and to do a water change, all I had to do was hook up the basement faucet to a hose, siphon out the bad water down the basement drain and fill up with good water.
Water changes in a living room tank are much trickier. You should get a gadget called a Python No Spill Clean 'N Fill, which is basically a water-powered siphon and a long hose. Very nifty gadget (and you should pop for the 50-foot hose, too; you’ll be glad you did.) Note: this is virtually guaranteed to be cheaper if you buy it mail-order, than if you invest in the old dusty one that your friendly neighborhood pet store happens to have lying around. I once saw one for sale at a Friendly Neighborhood Tropical Fish Store for EXACTLY twice what I paid for mine, mail-order. Sheesh.
I agree with Spathiphyllum that 10 gallons per goldfish is minimum. The usual rule of thumb that the pet store workers will quote you is “10 gallons per inch of fish”. IMHO, after many years of having both tropical fish and goldfish, this is a rule that properly applies only to small, cute, tropical fish that don’t excrete quite so spectacularly, in such long brown messy strings.
Goldfish should never be kept in one of those cute goldfish bowls which holds maybe a gallon of water. It’s like asking it to swim around in its own toilet bowl. How would YOU feel?
And don’t bother with those ridiculous air-powered floss and charcoal filters, they’re right out of the Stone Age. After you clean the fish tank, you gonna go out in the backyard and build your own little Sputnik model, Bobby? A job worth doing is worth doing well: get a hang-on-the-back power filter (they sell them at Wal-Mart).