hey, this is what the experts say:
Don't keep goldfish in a fishbowl. It is narrow at the top and not enough air can get into the bowl to allow the fish to breathe. An aquarium is much better because it is the top is just as wide as the bottom. When choosing an aquarium, buy one that is big enough to allow goldfish to grow. Yes, they can get big. The minimum should be a 20-gallon tank. If you buy an aquarium, you can use a good filter to help keep the water clean and you can have nice lights for showing off your fish. Be sure to turn off the lights overnight. You should have a cover for your tank, just in case you have lively goldfish that like to jump. Do not add tap water into the tank and then put your fish in right away. There are chemicals in tap water that can harm the fish. Let the water sit in the tank for a day or two. Change 1/3 of the water in the tank at least once or twice a week in order to keep the water clean for the fish. Do not empty the tank completely because you will lose the good bacteria that keeps the fish alive. For the water you will add to the tank, let it sit overnight so it will be room temperature and to allow the chemicals to evaporate. Use an algae scraper on your tank if you see a buildup of green stuff on the walls of the tank. Do not use a scrubber that is used in your kitchen because it will contain soap. Buy fish food that is made for goldfish. It contains the proper nutrients specially made for these types of fish. Not all fish need the same food. You can also buy frozen snacks at the pet store like tubifex worms or brine shrimp. Do not over feed your fish! Uneaten food will rot in the tank and make the fish sick. If your fish do not eat their food within 2 minutes of feeding them, it means you have fed them too much. Try to remove any food they haven't eaten or it will sink to the bottom and rot. Don't be fooled by fish - they always act as if they are hungry. hope this 'll help..all the best..
Goldfish are easy to care for. Just change water if not filters at least once per week. If you have chlorinated water you will need to use a chlorine remover chemical which can be purchased in pet stores which carry fish supplies. Or you can fill up a container and let sit for a few days to allow the chlorine to dissipate. Don't over feed fish, only give enough food that they will consume in a few minutes, twice per day. Goldfish can tolerate colder water so aquarium heaters are not necessary, they like water cooler than tropical fish, which usually like water temps 78 to 80 deg. F. Main thing is to keep tanks or bowls clean. If they are in a an aquarium with filters, change filter charcoal and filter floss once per week.
Do you have to clean the gravel at the bottom before you put the fish in or no?