It's a 2.5, I have one sitting next to my 5gal as a temp tank and it's half the size. P:
If you filled it and it only took 2.5 gallons of water, that tells you right there. xD It's not going to be different if you do it again.
@Chrys; If you bowl is not heated, unless your home is 85+ degrees consistently, the water is too cold. Considering that you don't know the temperature, either, I'm sure that's part of the problem. And yes, the water should be changed more often.
Try to look in to some cheap alternatives to tanks if you can't afford one. Critter Keepers are good, and I've seen a photo someplace of a tank fashioned out of an empty 2 gallon animal cracker container. You can still provide for your fish on a limited budget.
Last edited by Capricorn; 09-29-2010 at 10:22 AM.