Time To Clean The Fish Tank

I was feeding the fishes when I saw the other gold fish that was kinda weak.I got really worried so I called my husband.He told me maybe the gold fish was really full or maybe the tank needs to be clean.I asked when was the last time he cleaned it and he cannot remember,he said it was either Thursday or Friday.The water was kinda unclear anymore so I have decided to clean the fish tank,I pity the fishes!If I was them I do not want to be in a dirty tank,I do not want to drink dirty water.The other gold fish is still weak,I hope he will be fine,I do not want any of our fishes to die (two of our gold fish died already).Well,I am just going to observe them and hope nothing bad will happen to each one of them.