There are a lot of threads on this topic...I suggest looking them up. There are literally dozens of reasons we need to do water changes, whether your "levels" are "ok" or not. There are dozens of organic wastes and metals that build up that we do not, or cannot (feasibly) test for. Nitrate just happens to be a good, indicative, and easy to test for component. Also, fish excrete growth inhibiting hormones. If water is not removed to reduce these, they build up. The fish are exposed to too much of them. They are affected adversely.
Fish, unlike humans, live, eat, drink, breathe their underwater world. It (H2o) is literally absorbed throughout their entire body. As a result, many of their nutrients are taken from the water column. Water must be renewed to allow for this process.
In planted tanks, water changes reset the water parameters and allow for more accurate dosing. They also remove excess fertilizers that are not wholly consumed.
I do 50% changes weekly (or even biweekly if I feel like it - it can only help). After a water change, the fish often are more active and the cories will spawn.
As for making pleasure into work. I also like doing changes, usually. It's also probably the best opportunity to check the health of the inhabitants.
Fresh water is fresh water. If there were some way around water changes, we'd know of it. There is a reason we're all lugging buckets. There is a reason why the ichthyologists at public aquariums do water changes just like us (of course they have nice automated systems! Must be nice!).
EDIT:
Here's a quote from RTR:
Enclosed biological systems build up significant levels of organics - hormones, phenols, proteins, all sorts of junk - none of which are subject to hobby testing. Ditto for all the inorganics - minerals, etc. that are added even to unsupplemented tanks via fishfood and water additions - being concentrated to levels beyond plant usage even in planted tanks. In planted and supplemented tanks, obviously the buildup - as Len mentioned - can go even faster, and play hob with controlling nutrient levels. Water changes are cheap, simple, and reset everything dissolved in the tank to lower levels. The older I get, or the more experience I have, the more I am convinced that water changes are the best single thing that I do to protect and enhance my fish and their environment.
That's from this link: http://aquariacentral.com/forums/showthread.php?t=33374&highlight=hormones
But please don't get this confused with the school of thought that plantbrain talks of. It's a little different for the planted tanks (and not everyone agrees on that anyway)
One more, same thing more or less:
http://aquariacentral.com/forums/showthread.php?t=19324&highlight=hormones
I pulled those both from the Aquatic plants section, but the principles are basically the same. I dont feel like looking for the rest.
Fish, unlike humans, live, eat, drink, breathe their underwater world. It (H2o) is literally absorbed throughout their entire body. As a result, many of their nutrients are taken from the water column. Water must be renewed to allow for this process.
In planted tanks, water changes reset the water parameters and allow for more accurate dosing. They also remove excess fertilizers that are not wholly consumed.
I do 50% changes weekly (or even biweekly if I feel like it - it can only help). After a water change, the fish often are more active and the cories will spawn.
As for making pleasure into work. I also like doing changes, usually. It's also probably the best opportunity to check the health of the inhabitants.
Fresh water is fresh water. If there were some way around water changes, we'd know of it. There is a reason we're all lugging buckets. There is a reason why the ichthyologists at public aquariums do water changes just like us (of course they have nice automated systems! Must be nice!).
EDIT:
Here's a quote from RTR:
Enclosed biological systems build up significant levels of organics - hormones, phenols, proteins, all sorts of junk - none of which are subject to hobby testing. Ditto for all the inorganics - minerals, etc. that are added even to unsupplemented tanks via fishfood and water additions - being concentrated to levels beyond plant usage even in planted tanks. In planted and supplemented tanks, obviously the buildup - as Len mentioned - can go even faster, and play hob with controlling nutrient levels. Water changes are cheap, simple, and reset everything dissolved in the tank to lower levels. The older I get, or the more experience I have, the more I am convinced that water changes are the best single thing that I do to protect and enhance my fish and their environment.
That's from this link: http://aquariacentral.com/forums/showthread.php?t=33374&highlight=hormones
But please don't get this confused with the school of thought that plantbrain talks of. It's a little different for the planted tanks (and not everyone agrees on that anyway)
One more, same thing more or less:
http://aquariacentral.com/forums/showthread.php?t=19324&highlight=hormones
I pulled those both from the Aquatic plants section, but the principles are basically the same. I dont feel like looking for the rest.
Last edited:
) so since they are solely for pleasure, would you not clean it's litter box, or clean the area where your dog takes care of its business outside? Of course you'd clean it... and you most likely wouldn't wait until it stunk to take care of it! It's the same deal with a fish tank... 
