1 of my goldfish has red on its gills and it looks like blood! It keeps on going to the surface to gasp for air and it has been eating less. I have 2 goldfish and they share one tank, but the other one seems fine! How do I cure the other one? Please answer quickly!!

As per C Robbins:

He has now been in there long enough that his waste and respiration have used up the oxygen in the water. He is going to the top to try and get enough, but it's never going to happen in there I'm afraid. It's a shame the fish store people didn't give you better information about it. I'm sorry that has happened to you.

Contrary to commonly believed, goldfish just cannot live in a fish bowl. Goldfish need 10 gallons per fish and good filtration to thrive. Maybe a 5 gallon would be okay for a few short months, but he definitely needs much more room and oxygenated water from a filter. Here are some web pages about goldfish and what they need.

Goldfish Care Basics - The First Tank Guide - Tips for Giving Your Pet Goldfish a Long and Healthy Life (http://www.firsttankguide.net/goldfish.php)
Goldfish Care (http://www.kokosgoldfish.com/care.html)
The Goldfish an Aquarium Board (GAB) Article - Goldfish Basics (http://thegab.org/Articles/GoldfishBasics.html)
Goldfish FAQ (http://www.flippersandfins.net/goldfishfaq.htm)

Good Luck

Stratmando is absolutely right. Goldfish need at least 10g per fish and a good filtration system IN PLACE before you get fish in the water.

And as a side note the fishes gills are suppose to be deep red. Like raw prime steak. It's the gasping and floating that is the problem.

Another good site for goldfish is www.koivet.com