First off me and the fishie would like to thank you for your efforts.

I had a look at Wallmart.com and that filter may be a bit large for the 1 gallon tank, but it should be very good for the 10 gallon tank, so you may want to save it.

The worst thing that people stumble on when they get a fish tank is something called "new tank syndrome," and yes, there is one for old tanks too. When fish go potty in the tank it releases ammonia which is toxic, but after a few weeks or months bacteria naturally grow that eat this, but they produce nitrites, which are also toxic. Well... them more bacteria grow that eat the nitrite and make nitrate, which any green plant will love as it is a natural fertilizer, and isn't particularly toxic to the fish anyway.

The trick is to keep your fish alive until the bacteria all grow! That means lots of water changes, your current twice a week should be good, but see if you can get some test strips for chemistry. If the numbers for ammonia or nitrite go high do a daily change till they go back down.

When you get your new tank if you can set it up you can use ammonia from the store (get the cheapest kind that is just ammonia and water) to spike the bacteria into growing. I did that once and got all the bacteria my fish would need in a 55 gallon tank in 2 1/2 weeks.

Another way is if you have a friend with an established healthy tank ask them if you can get a fresh dirty filter from them, take it home in water ASAP and squeeze it out into your tank (no fish there yet!). That can jump start their bacteria in your tank.

"Old tank syndrome" happens if you don't clean the tank and gravel. Bad things can grow in the bottom gravel so I have a siphon I use when doing water changes to vacuum out debris.

Thank you for your help! I read about the nitrogen cycle, and will definitely keep that in mind when we're able to get the fish into a bigger tank. I will take your advice with regard to setting up the new tank. He (or she?) is already looking healthier than he did when he arrived, has brighter color and has even grown a little. I'm surprised at how much personality a Goldfish actually has. :-)

Thanks,
Cj

Yes they are delightful. If you get more fish the fun part is seeing how each and every one behaves just a little differently from the rest. Some of my fish scamper to the bottom when I open the tank to feed them. Others almost jump out the top and some will even nibble at my fingers.

I'm happy your little fellow is looking better.

Boy or girl? Boys get little bumps on their gill covers, girls don't.