How to Care for Goldfish/guppies

Like Bobbi said...sometimes they don't survive that process.
Goldfish are a pain in the butt.
I had some that grew to be big enough to eat for dinner. ;)
I will never own goldfish again. Too. Much. Work.
If they don't make it...
Betta fish are great low maintenance fish.
I have one now, he's been w/ us for almost 2 years.
Loves his small filtered tank.
I clean it every couple months, squirt a bit of water balancer in and am done!
HTH! GL!
Oh yes! You absolutely must have a charcoal filter for goldfish!
Good point, Peg! :)

You don't have the pH right in the tank yet. Starter fish (goldfish) don't always survive the tank set up. It takes awhile to get the proper pH balance in the water. You are probably changing the water too much and upsetting the natural balance.

Go back to where you got the fish and talk to them about it. Get a water testing kit and have them teach you how to use it, and how to get the water properly balanced. You might have too many fish in too small of a tank. It sounds like you're getting acid build-up. Their waste isn't being efficiently taken care of by bacteria so the water gets cloudy. Sometimes it takes weeks to get the proper balance.

tetra.com should have a lot of the answers you are looking for.

From my own personal experience - do not put anything in the tank with gold fish! They will eat everything!!!

We've had both.
We had a gold fish that lasted 2 years and now have O. guppy that my son got in first grade (he's in 3rd).

Goldfish are really dirty fish!

Maybe your bowl is too small. Get a 2 gallon O..

I put the fish (separate times: goldfish or guppy) in a large fish bowl (no filter, bubbler, etc.) and cleaned the tank about once or twice per week. Gravel in the bottom. Use two gallon jugs to "distill" the water for 2 or 3 days before using it in the bowl. Goldfish food.
Get a net to scoop out the fish first, transfer into a small cup with clean distilled water, dump the water, rinse the gravel, scrub & rinse & dry the bowl. Rinse the bowl really well after you clean it well with dish soap. Fill again with the cleaned gravel, standing water, then pour the fish back in.