Are Water Changes Actually Necessary?

[Star_Rider]

kazvorpal,
i am curious how many 'difficult' or wild species fish you have kept.

I , and I know jinkzd and a few others, do keep wild species.

some of these you have to maintain extreme water conditions. acidic pH, with very low to no gh/kh and peat to help reduce pH.

I am relatively lucky as my water is pH 6.8-7 with 3-4 dkh and 5-6 dgh still i run water thru a RO/DI and add peat to lower pH.

some of these wild species are extremely sensitive to TDS which climbs simply from feeding.
they begin to show signs of stress quickly so it is imperative to maintain stable water.

on the flip side I maintain marine tanks where water changes also add stability to the system , replenishing many chemicals in the tank.. here I maintain deep sand beds in the fuge and live rock(which also helps with nitrogen exchange)

deep sand beds can be tricky and must also be maintained..usually in marine systems with the use of invertebrates.

btw skimmers are for use mainly in marine tanks where SG helps produce skimmates.

 

[Fishfriend1]

opcorn::read:

 

[kazvorpal]

That is called old tank syndrome and is well known. If done regularly and frequently, crap the fish get used to won't accumulate. Anyone who has had any experience in fishkeeping knows if you suddenly alter parameters, even if it's for cleaner water on a neglected tank, you will stress the fish.

I do 50% weekly water changes on all of my tanks. I've never noticed any stress from my fish during or after a water change.

But you are ignoring the fundamental question, inserting your assumption even into your wording:

Who says the tank is neglected? If you suddenly add a fish to an established tank and it dies, this is a sign of badness, but if you add a fish to a clean tank and it's killed for the same reason, this is NOT?

"Old tank syndrome" is simply a way of saying "water changes cause stress on fish", with the oldest tanks being the ones where the stress becomes so obvious that it kills.

An anecdotal example of the benefit of water changes is my brother's tank. He was bad about doing water changes, might do them once a month. Since I got on his case and he stepped them up to weekly changes (starting slowly and working up) his fish have had noticeable growth and one species started spawning. All in the span of 4 weeks (Thanksgiving to Christmas).

Again:

Water changes cause fish to spawn, because they STRESS the fish, simulating a change in seasons (dry to rainy, for example).

Fish need to be healthy to spawn, but the actual spawning is often triggered by stress. Same with many other animals. The stress of cold weather triggers mating in many animals that gestate until spring. The stress of low nutrients causes nightshades to bear fruit.

Too much of aquaria's conventional wisdom comes from inductive reasoning, like "the fish look more active when I change their water, and they spawn, so it must be good"...two signs of stress.

Oh no, people on Jamaican beaches move so slowly, they must be unhealthy...they get so much more active if it gets cold and rainy! Cold, rainy weather must be better for humans!

 

[bluekrissyspike]

i change my water because my fish seem to be happier(more colourful and active) after i do, to remove poo and left over food, my plants start to die on me if i don't and it makes my tank look nicer without little flecks if who knows what in the water. why keep fish if you don't want to look after them

 

[Fishfriend1]

"You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist." - Friedrich Nietzsche
Im ganna keep posting this to help show that everyone has there own way and it is wrong to say that there way is wrong. Cause ur way is too.

 

[12 Volt Man]

If you once worked at an LFS, then surely you had people come in with mysteriously dead fish, and learned they'd recently done a water change. Or perhaps you didn't pay attention to that, because you weren't expecting it to be causal...but it can be.

if they have a tank with old tank syndrome (ie very low pH) and then do a large water change rapidly bringing the pH up, pH shock can kill the fish yes.

but its not the stress of doing the water change as far as you should not do them to avoid it, its that by rapidly changing the PH (from a level so low) to a level much higher, yes you can kill fish.

the point here is that had water changes been done properly to begin with, the problem never would have surfaced, the water change that did the killing would not have caused the rapid pH climb that it did and the fish would have been fine.

again, water changes are important.

 

[12 Volt Man]

Obviously, some amount of acclimation COULD fix that. "Used to" is not a static condition

doubtful. if your pH is very low from neglect and you introduce fish like cyprinids (for example) they won't do well.

but south american fish may be more tolerant.

hence, the new fish doesn't make it.

the old fish are fine. for now. eventually the pH drops low enough and the nitrates can get high enough and you get lots of problems eg. fungus, popeye etc. That is an old-school assumption.

If you have a deep sand bed, or a mud filter, or a plenum, or a few plants and a protein skimmer, or ceramic foam plates in your tank, then the nitrates do NOT build up, but in fact can be problematically low.

but now you are getting in the salt water world where yes, people with reef tanks do FAR less frequent water changes than us mainly freshwater people do..

so we went from comparing apples to apples to apples to oranges..

 

[Hollygirl]

I test my water and have never had any problems, but just like others have stated the fish seem to actually enjoy the partial water changes.

While your theory is interesting in the changes not being necessary, consider this:

How good does it feel when you open a window on a nice day? While the fresh air exchange is not necessary, it makes us feel good.

That's pretty much how I feel about partial water changes.

 

[Fishfriend1]

just top the tank off when u need to and the fish will be fine. Your doing a 10% change when u do that anyway lol.

 

[kazvorpal]

kazvorpal,
i am curious how many 'difficult' or wild species fish you have kept.

I tend to avoid them, except the ones that actually aren't as difficult as reputed.

There are absolutely some situations where you should do X. I was asking for examples of those. You have to do all kinds of crazy things to keep rams (freshwater) or seahorses (saltwater) alive and healthy.

But not in general.

on the flip side I maintain marine tanks where water changes also add stability to the system , replenishing many chemicals in the tank..

Replenish chemicals?

What chemicals are in tap water?

Or do you mean because we add new, synthetic sea salt that contains trace elements in them?

Water changes, normally, are about REMOVING chemicals, not adding them. Except for the elements in Instant Ocean, reef crystals, et cetera.

And you can definitely add those trace elements without a water change, if you prefer.

here I maintain deep sand beds in the fuge and live rock(which also helps with nitrogen exchange)

deep sand beds can be tricky and must also be maintained..usually in marine systems with the use of invertebrates.

btw skimmers are for use mainly in marine tanks where SG helps produce skimmates.

I keep bumping into freshwater people who claim to use them, although I had the same impression as you.

But I maintain both fresh and saltwater tanks. Well, to be accurate, brackish cichlid, and marine reef.

A DSB shouldn't just "help" with nitrogen exchange. It should render the cycle so effective that you have to worry that some corals and plants aren't even getting enough nitrates to thrive.

With a DSB tank, water changes can be necessary, but not nearly as often as almost any other kind of tank. I suppose the kind that needs them even less frequently is a freshwater deep sand/mud bed.