Fish Tank Retailers

TANK MAINTENANCE QUESTION!!?

I was just wondering when it is best to do water changes (once a week, every two weeks, or later/sooner). I am curious because I have filtration and all and retailers at pet shops say change it every two to three weeks whereas a book that I read today about FW aquariums recommend like every few days. Wouldn’t this shock the fish??? The book also says to take out 50% of the water, whereas retailers at pet shops and myself only change 20% of the water. Yea, the book says “The cleaner the happier”, but won’t this hurt the fish in the long-run??
Please help!! thanks…

Maybe I have just been lucky. I have never changed the water in my tanks once I felt they were established and healthy. I would always keep opened bottles of water under the fish tank stands. As the water evaporated, I would just enough to fill it up again. I had live plants in all my tanks. I had very good filtration. The only real clean up I might do is when I felt the grave/sand mixture was looking dirty. Maybe every 6 to 8 weeks. The water I kept to top off the tanks was in open bottles. This way the water would age like the water in the tanks. I would agree with you that too many water changes is not healthy for the fish.
And “The Cleaner The Happier”…No, I would think not.
You have to remember too that a retailer is trying to sell all his fish. He might only keep most of his supply of fish for a couple of weeks maybe. It would be to his advantage to keep the water as clean and as clear as possible. I hope that helps…

A Tour of Austin Aqua Farms