Hello Everyone, A few weeks ago my dad and my sister stopped at the pet store and bought us 4 little goldfish. On the ride home one died, and a few days ago, one more died (we crowded them in a 1 gallon tank with no filter). Finally, I convinced my mom to let me take care of the gold fish, so we went to the pet store bought a 20 gallon tank, and kit, filter ect., and then we went home and set it up. There are currently 4 gold fish living in the 20 gallon tank, the person at pet co said thats more than enough room. I was told to do a 10% weekly water change, (I have a suction thing that can help me clean the gravel ect.), and when I put new water in I use regular tap water with some extra liquid thing (forgot the name), you can add to make the water safe. I also have a led light in the tank, and some food for them. I feed them regularly following the instructions on the food container. The tank's temperatures don't switch so I don't think the fishes are under stress (except for when I took the bag from the pet store dumped the fish in the water and called it done rather than allowing them to situate (sorry fisheys.). Each fish is ~1 inch long and my tank has 2 castles and 6 fake plants in it for decor... I am not sure if my parents will let me spend any more money, and I do not have a test kit. I do have a heater but heard that gold fish do not need heathers. I also bought some gravel, but it definitely seems like not enough so my parents said next week I could go get some more. My only questions now are do I need to do anything else. I'm hoping to be able to get more tanks and fish and maybe even build my own pond... and was wondering if you have any advice. Also since the petco person said 4 fish in 20 gallons is easily more than enough, can I introduce more fish or is that good. Well, thats basically my fish keeping knowledge (it is my first day), so looking forward to your replies!