Water change frequency?

[RobVG]

Established12 gallon tank, 2 goldfish.
Air stone operated under-gravel filter with 2 uplift tubes.
Hoviran 7 in 1 test strips.

It's been 9 days since last water change. Strips are showing "0" Nitrite and 10 Nitrate.
Fish seem "happy".

I've always done weekly water changes, but I'm wondering if I should trust the strips and extend the time between changes?

 

[Essjay]

Water changes should not be done on the basis of nitrate readings. There are many other things which build up in the water, things we cannot measure from hormones secreted by the fish to other waste products. I used to work in a hospital lab and we tested urine for a whole host of things. Fish will excrete similar, if not the same, things as us.

Provided ammonia and nitrite are zero, weekly water changes should be done regardless of 'good' nitrate readings especially in tanks with messy fish like goldfish. If ammonia and/or nitrite ever show up, more frequent water changes need to be done.


Incidentally, are you aware that 12 gallons is too small for even one goldfish long term? You'll need a bigger tank for them before long.

Goldfish For Beginners

Types and Sizes of Common Goldfish Breeds First of all, never underestimate the size of fully grown goldfish. There are no 'dwarf' breeds of goldfish, whatever 'the man in the shop' might say; even the smaller 'fancy' types have the capacity to grow to a good six inches/15 cms in length...

www.fishforums.net

 

[RobVG]

Thank you for the info and yes, we are aware we're going to need a bigger tank.

 

[anewbie]

Thank you for the info and yes, we are aware we're going to need a bigger tank.

Sooner the better; if a large fish is left in a small aquarium too long it can become stunted and develop long term health issues.

 

[Uberhoust]

I find I change 50% of my water in my tank one a week, or 75% every two weeks. With a goldfish I would look at 50% weekly.