Originally Posted by braykbeat
My girlfriend just set up a 10 gallon tank with 2 goldfish. How often should we change the water? I was thinking 1 time every week/week and a half. How much water should we change? Do you think the tank is too small for the 2 goldfish? they're about an inch and a half and 2 inches. I thought the general rule was 1 inch / gallon of water. but the goldfish produce a lot more waste.
Well a 10G would be ok for goldfish temporarily IF you have a good filter, AND the tank is cycled.
There are many problems, however.
1. Goldfish are a coldwater species, which means the inch per gallon rule is even less accurate than normal. If I remember right, a coldwater tank can only hold like an inch per 4 gallons. (cold water holds less oxygen than warm water)
2. If the tank isn't cycled, they may very well die. You need to do WC's DAILY and buy a test kit for Ammonia, Nitrite and Nitrate minimum. Ammonia should be 0, nitrite should be 0, and nitrate should be existent, around 5-10. (Nitrate is harmful, but it's the least harmful product from ammonia. If there's 0 nitrate, your tank is probably not cycles. A little bit of nitrate just means your bacteria is doing it's job.)
3. Goldfish, even common goldfish, grow extremely large and will outgrow the 10G in no time. I'd say a minimum of 20g+ for two grown goldfish, and you might need a tank even bigger.
4. If it's possible, I would take the goldfish back and wait for your tank to cycle. Once it's cycles, there's many fish species that look like goldfish...
If your tap water has a lower PH, look for tetras that you like. (Ember tetras for example)
If your tap water has a higher PH (around 7.5) then maybe orange platys or swordtails.
If you're REALLY lucky and it's 7.0, you can get either. All of those fish I mentioned are tropical fish, so they like warm water- get a heater, and you can do something closer to the 1inch/per gallon.
I hope I covered everything... If you have any questions, post them here or feel free to PM me.