While it isn't required that goldfish have an air pump in their tank. It can help your tank life by providing valuable oxygen to the fish. This isn't specific to just goldfish, as all aquatic life can benefit from the presence of a air pump. If you notice your fish swimming with their lips on top of the water level most likely they are trying to get air. This is especially true for tanks that have canister or over flow filters where the water is pumped and filtered without making contact with air.
A goldfish does not need an airpump, it needs 3 stage filtration and good water movement from something such as a box filter and/or power heads. A goldfish, however, is not suited for a 5 gallon tank. 10 gallons per goldfish is the recommended minimum, as they grow very large and require more oxygen than almost any other fish. I would recommend something smaller such as rosy minnows, guppies, or if you get a heater, small tropical fish like tetras. ALL fish however, need filtration, not just an air pump.
That you need a new goldfish
there are three basic breeds: fantail goldfish, comet goldfish, and common goldfish. if you are getting goldfish for the first time, i would recommend common goldfish as they need the least care.
The answer is no. People usually think that goldfish get lonely and depressed. This is not true. Goldfish are fine on their own! People usually prefer 2 or more
goldfish need to lay eggs. Because if they don't no goldfish would be alive and would not be any more so they would become gone forever.
Yes, goldfish are very messy. Goldfish need 10 gallons per fish, you actually need a 20 gallon tank or about a 70 liter tank for 2 goldfish. But the small tank will do while they are small, you will need to eventually get a larger tank.
That is the normal way to inflate any tire.
Well yes you need a male goldfish and a female goldfish to have babies but it takes allot of time to breed them.
Regardless of the type or size of goldfish the minimum acceptable size of an aquarium for a goldfish is 30 gallons. Buy a tank that is at least 30 gallons if you plan to have goldfish. You can comfortably fit 3 goldfish in a tank this size but no goldfish in a tank any smaller. Goldfish are essentially pond fish and need lots of space to swim; they will not thrive in a small aquarium.
The goldfish should never be in the same tank as guppies. Goldfish are coldwater fish and need to be kept below 70F. Guppies are tropical fish and need to be kept above 70F.
Goldfish just need a plain bowl and some plants
You need to provide 1 gallon of water per inch of fish. Goldfish get along fine with other goldfish.