I bought my daughter the Glofish tank set and 3 glofish. No more than one day after we set it up, the tank had a foul odor... so I re cleaned the entire tank only to have it smell just as bad a couple hours later...
Cannot figure out why it is stinking and really do not want to have to change the water on a daily basis... because of what it can do to the poor fish and the inconvenience that it brings...
If anyone has any advice, we'd greatly appreciate it!

Thank You!!

What kind of filters are you running? Have your added beneficial bacteria? Did you let the tank cycle before you added the fish? I would start there. Past those questions I have never heard of a tank even with goldfish in it smelling that bad that fast.

How big is the tank and what kind of filters are you using? Sounds like it is too small for 3 goldfish and the filter is not sufficient. Goldfish are messy... they foul the water fairly quickly.

It was a day before I bought the fish so the tank did cycle... it is a three gallon tank that came with filter. I finally changed the rocks and filter again and I removed a neon car statue that was in the tank. It has a normal fishy smell now and not the putrid one. Thank You for all the advice!!

The cycling process takes longer than a day- usually more in the 4 to 6 weeks range. You need to keep an eye on the water quality until it finishes since you'll be doing a fish in cycle it seems. As to why ti would start stinking so quickly? Best guess is overfeeding. If the tank isn't cycled the food will make a mess of things pretty quickly.

fish in cycle (http://www.aquarium-setup.net/so-you-didnt-cycle-your-aquarium-before-adding-fish/)