Need Help mainting an overstocked fantail goldfish tank ?

[Monster Goldfish]

Hello Everyone

I have 4 goldfish fantail , 2 small which are about 2.5 inches long and 2 bigger ones which are about 4.5 inches long in a 20 gallon aquarium although water capcity is only 16 gallons . I have a Chinese cheap internal filter which comes with one sponge media . It is supposed to filter 800 LPH which is 222 GHP . I have small white pebbles as substrate and one plastic plant ( were two but I removed one because it broke while cleaning it ) . I also have a background that makes the aquarium look heavelity planted .

The help I need is ...

How can I keep the aquarium as healthy as possible having the pre-mentioned 4 goldfish knowing that I'm planning on getting Aquaclear 50
soon and I'm planning on getting a 75 gallons tank next year or so.

Please give me as much adivce as necessary how much should I change the water ? how many goldfish sticks should I feed them because they can eat very fast so the 2 minutes rule is not working for me they eat their food in seconds ? If you have anything you want to advise me , please do not hesitate.

Regards
Mohamed Nagem

 

[Laser]

I would get the new filter as soon as possible. To be honest I would do 50% water changes everyday, at least every other day, until you get them in the 75 gallon.

 

[Brandon K.A]

I agree with 50 percent every other day. New filter would probably help reduce this. Overfiltration will really help.

 

[Monster Goldfish]

Thanks guys , this thread is repeated by mistake , this is the mew amd improved orginal thread : Click here