I use a 20gallons for one goldfish rule. So my four feet tank can keep six goldfish only lo because of goldfish body shape the stomach is small very compact, so food will be digest very fast also lo.

What size of tank you use now? For goldfish go bigger tank.

You can check at this website:
http://en.wikipedia.org/wiki/Ranchu
http://www.youtube.com and search for Ranchu

1) Must know how to choose good healthy goldfish from the shop if not later will face with sick goldfish.

2) The tank must be properly set up before buying a goldfish, one week or two week earlier.

3) Cycling the tank the Most Important thing, if not proper cycling you will face with high ammonia and nitrate level this will kill your goldfish.

4) Each goldfish need 20 gallons of water, so must use big tank.

5) Good fish food that will not cloud the water.

6) Goldfish tank need a powerful filter to clean the water.

7) Weekly maintenance 25% water change.

Haha, to choose a good healthy goldfish need experience, by looking at the body look for injury,any spot,any sticking thing on the body. Mostly healthy goldfish will swim around happily.

Goldfish can live longer than that if proper enviroment is achieve, there is a lot of sign shown by goldfish floating like not enough O2, dirty water etc.

Good fortune or Not good fortune, feng shui or what ever it is, it is a hobby, i'm still need to work everyday for money. Do you think if you got good feng shui and good fortune but not working will money come to look for you? Hahaha.....

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Added on September 18, 2007, 11:47 amSome ppl pay for expensive pet because they think expensive pet that offer in the shop can live happily in their care/house but fortunately thing goes difference way. So whether the pet is expensive or cheap the most important thing is we ourself must be very prepare before buying a pets.

This post has been edited by kent kt: Sep 18 2007, 11:47 AM

To keep 20+ goldfish you need a 400+ gallons tank because each goldfish need 20 gallons of water. Floating upside down because not enough of O2, or swim bleeder disease, air trap in the blader.

Before I setting up my goldfish tank i'm thinking of using UV filter for my goldfish tank also but after setting up everything and run the tank for four month plus without using UV filter everything found to be running quite well no disease,not losing any fish, only the water got a little bit of golden green colour.

There are two type UV filter in the market,
1) The external canister filter with build in UV light.
2) The UV light only, just connect it to the filter pump.
The cost will be base on brand and watts. The higher the watts and of course the costly it will be.

Lifespan for goldfish is depend on well you taking care of it.

If this is a tank in the fish fish shop it is ok, if otherwise then it will be a problem to maintain the tank. Overpopulated tank.

Hopefully your fish still ok, my one got problem already after Raya holiday for 4 days.

It just like a wound,no more scale,when it's happening?