Most pet shops will tell you to set the tank up and let it run for awhile before you add fish. Then they test the water and say.. no ammonia, you can add fish. They call this cycling, but it isn't. Of course there is no ammonia, there aren't any fish to produce ammonia. Then you buy fish, they get sick and/or die. The shop sells you medication or more fish. They make more money. Without an ammonia source, no bacteria will grow. You cycle a filter by either adding ammonia to the tank( fishless cycle) or by adding some very hardy fish, testing the water daily, and doing large water changes daily (fish in cycle). Don't feel bad, this happens ALL of the time. Right now you don't have any choice... you are doing a fish in cycle. You NEED a test kit. Get one right away. A liquid test kit is best. The strips aren't very accurate. You will need to test the water atleast once a day. If you get an ammonia or nitrite reading of more than 0.25, do a 50 - 75% water change. I'm sorry this has happened, but all is not lost. You can turn it around and have a happy aquarium. Get your daughter involved with the process. Tell her what's going on and have her help "fix" the problem. My kids got so involved when they were young.