aquarium

Question
My goldfishes most of the time swim on top,looks like taking oxygen.I have 10 gallon aquarium ,2 airstones and one filter.

Answer
They are telling you there is not enough oxygen in the water. 1 goldfish should be n a 20 gallon aquarium with a filter made for a larger tank. Not sure how many you have, but you really need to get them in the right size home if you want to keep them happy and healthy. The filter is most likely not able to filter the waste and add oxygen because there are too many fish and too much waste. I would recommend removing them from the ten gallon and place them in a cycled tank that is the right size. One goldfish needs 20 gallons with each added fish 10 gallons more. So, If you have 2 goldfish, they should be in nothing less than a 30 gallon tank. 3 should be in nothing less than a 40 gallon tank and so on. My suggestion is to upgrade your tank.