Read in some fish food packaging "If more than half the tank of water has been changed,do not feed your fish for 24 hours"

Was wondering if any bros adopt this practise and if so,why?But I do know some lfs owners who keep their fishes in outdoor ponds do not feed after rainfall.

Also,does anyone here starve their fishes for a day per week as recommended by some websites?And what's the reason behind it as well?

Honestly, I never practise that. I believe some fishes are not used to the change in water parameters and temperature, etc after water change and they might not want to eat. There could be some other reasons I don't know of...

I do feed my fishes within 2-3 hours after water change. All my fishes lives in green water and I make it a point to bring the temperature of new water to about the same temperature of the previous brew. So I supposed there's isn't much change to their surroundings, except that the water is clearer... And they still eat like pigs after water change

I wont advise feeding after huge water change until after 2-3 hours unless u adjust the new water chemistry to be very simliar to yr old water. For me, after a huge water change, my goldfish will remain motionless at the bottom of the tub. I believe its the large KH/PH variation that causes that to happen. Usually the next day, they will become active again and somtimes, "turned" on their sexual mode . Simply not interested in food except chasing each other around the tub.

If yr goldfish remains active 3 hrs later after a huge water change, i guess theres no harm for u to feed them.

My 2 cents on this issue...

I always do 100% water change and do it no less than once a week.

I always feed 30 minutes after water change. If my fishes don't eat the pellets I will suspect something is not right with the new water, which fortunately seldom happen. Fact is my fishes appear even more active after a water change, which makes me happy, which makes me change water religiously.

A fish becoming listless and staying at the bottom of the tank after a water change is experiencing pH shock. Chances are, your old water's pH have dropped significantly becoz you didn't buffer it with baking soda.

To verify this, test the pH of the old water and compare it to the new.

To prevent this, always apply baking soda to your water to buffer the pH. This way during water change, the old water and new water's pH are near identical or don't differ greatly.

The correct dosage of baking soda to "up" the pH is by testing the water with a kH kit. As a general guideline, 4dkH should give you a pH of mid 7.