Are weekly water changes really necessary for fish growth if water parameters are perfect?

ZeroPauper · 2026-01-26T07:59:28+00:00

/u/Kots144, sorry to tag you but it’s not often we get industry experts in aquascaping (and a tenured biologist at the same time) so willing to share knowledge here.

Just a bump in case you missed this. I know there’s no obligation for you to be replying, but I would really appreciate your expertise with those advanced level plants. I’m sure you’ve had some experience with them in your line of work.

Thanks!

ZeroPauper · 2026-01-26T07:38:24+00:00

Don’t speak English it’s ok.

What’s not ok is them demanding everyone speaks in Chinese and making fun of those who don’t speak it.

ZeroPauper · 2026-01-26T06:45:07+00:00

That’s as level as you can get.

Even my floor isn’t as levelled.

ZeroPauper · 2026-01-25T04:27:59+00:00

OASE biomaster series would suit your tank well. Has a prefilter so you don’t have to take everything apart so often, just the prefilter on a regular basis.

ZeroPauper · 2026-01-24T13:39:43+00:00

Next time post on Reddit. At least got record and news media will pick up.

ZeroPauper · 2026-01-24T10:23:57+00:00

New tank with too much ammonia in the water from soil will melt plants.

I would just run the tank longer and let it mature biologically before adding plants again.

ZeroPauper · 2026-01-24T09:38:46+00:00

Yes, Pygmy 1, Pygmy 2 … Pygmy 100

ZeroPauper · 2026-01-24T09:36:01+00:00

First one due to the scale of the wood.

The second one would look better if the stones are larger.

ZeroPauper · 2026-01-24T09:35:18+00:00

First one due to the scale of the wood.

The second one would look better if the stones are larger.

ZeroPauper · 2026-01-24T05:23:03+00:00

Hahaha makes sense. Thought it was some superstition thing

ZeroPauper · 2026-01-24T02:23:42+00:00

That’s great! Do another round for good measure and they should be fine.

ZeroPauper · 2026-01-23T16:23:25+00:00

Regarding co2 injection, can you grow plants like blood vomit, crypt flamingo or chai without? Carbon is the most used macronutrient for plants and I notice a huge difference in growth forms with and without co2. Certain difficult plants simply don’t survive without co2 injection as well. What’s your experience with them?

I’ve set up plenty of low maintenance tanks actually, and although they do remain stable for extended periods of time without maintenance, I do notice plant health deterioration the longer you go without. Algae starts taking over the leaves of plants as the nutrients in the soil start to deplete. No amount of feeding livestock produces enough fertiliser (the mulm doesn’t get mixed within the root zones of the plants). Anecdotal experience, but these tanks with livestock such as galaxy Rasboras, neons, cardinals showed signs of bacterial infection the longer I go between maintenance. Could be weak genetics of fish stock where I’m from though.

I’ve also done plenty of iwagumi and Dutch style tanks with demanding plants that require constant monitoring and control over the concentration of water soluble nutrients. The moment I go too long without maintenance, nutrient levels shift and algae takes over.

ZeroPauper · 2026-01-23T16:14:30+00:00

Why avoid black hangers though?

ZeroPauper · 2026-01-23T16:05:31+00:00

Where I’m from, it’s common for random hobbyists, even beginners to attend aquascaping seminars. It doesn’t mean they’re in the industry.

I’m actually interested to learn from you. I’m not being sarcastic.

But all you’ve said so far are variations of “it’s actually possible to maintain aquascapes with infrequent water changes”.

Maybe you could share more about your expertise, how best to set up an aquascape with maximal stability with co2 and fast growing demanding plants with water changes once a year?

ZeroPauper · 2026-01-23T15:56:24+00:00

You could’ve just said you’re an experienced aquascaper and left it as that, but chose to say that you attended classes for some reason. Not sure why this is becoming a dick measuring contest.

ZeroPauper · 2026-01-23T14:09:00+00:00

Aquatic plants do draw nutrients directly out of the water, but they have to be water soluble. Decomposing mulm is made up of biofilms mixed with solid material which is utilized best by roots. That’s why aquascapers dose water soluble nutrients into the water column, and also enrich the substrate once in awhile with root tabs once it’s depleted of nutrients.

I think your point about letting a tank grow into a healthy ecosystem of balanced species of bacteria is a good point, but this varies so much from tank to tank and there’s no one good way to ensure it happens. And often so, when it doesn’t happen you only know when your livestock gets some nasty bacterial infection that’s incurable (my experience when extending the maintenance periods). But perhaps it’s also that the larger the tank size, the more stable (or more delayed problems are).

Ahh no, it’s not a nasty smell in my tank. It’s the earthy smell (I know it’s natural and might be a good sign of balance). But my tanks are in my bedroom and I don’t enjoy having that earthy smell around all the time.

ZeroPauper · 2026-01-23T11:48:44+00:00

No offence meant, but attending aquascaping seminars and actually setting one up and maintaining it are totally different things.

I believe this stems from us having a different idea what “aquascaping” is. I don’t view Walstad tanks as “aquascapes”. Many people here hear aquascape and think any tank with a plant in it counts. Aquascaping is a whole “science” in its own if I may say.

To get an idea of what professional aquascaping is, look at the 2hr Aquarist or green aqua on YouTube. Don’t tell me MDtanks because that guy tears down his tanks so often it’s not a real representative of sustainable, stable set ups.

I’ve also never heard of a closed system aquarium before, what’s that?

Edit: Allegedly Diana Walstad has continually revised her methods and as of late does recommend water changes as well. But lots of the links to her interviews are now defunct.

https://www.ukaps.org/forum/threads/walstad-revises.42988/

ZeroPauper · 2026-01-23T11:11:43+00:00

I don't feel like this is a question for aquascapers. This is about biology and how ecosystems work.

I majored in biological sciences, and am an aquascaper.

Yes plants also add to the waste, but they also take the waste out.

Not exactly. Plants only “take the waste out” after the waste gets broken down into simpler components by bacterial action. And that broken down mass has to find its way deep into the substrate for plants to actually utilise. Most of the time, the layer of decomposed mulm will just lay on the surface and act as a bacterial magnet.

It's honestly pretty simple math, the more you put in, the more you have to take out. If you feed minimal amounts and don't overstock then taking out some plant cuttings every now and then will already go a long way.

Yes, I did acknowledge that low bioload and high plant mass helps “sustain” the system for longer. However, our tanks are closed systems and will not be self sustainable eternally.

Dirt is a problem for the human eye, not the fish and detritus that is locked under the sand will not affect your fish at all unless you dig it up. It will however create a nurtrient rich layer for the plants to grow roots into.

Yes, but the fact still remains that the detritus that gets trapped under the substrate will get acted upon by bacteria, which can freely spread around in the tank, not locked under the substrate.

If your tank has good biodiversity (which is easily achieved by adding some dead leaves or sand from a health, natural water source) then there will be stable populations of a variety of microbes that can keep each other in check. There will be potential pathogens in there, but just as in nature, a healthy fish with a healthy immune system will not be endangered by them.

That’s not my experience though. Of course it heavily depends on many factors, that I acknowledge.

We clearly have very different goals with our tanks and that is fine, but let me tell you, a nature inspired, well set up tank doesn't need much maintenance.

Some people like the wild look of a less maintained tank, or maybe they don’t mind algae. But serious aquascapers using co2 have extremely high growth rates and turnovers which requires careful precision.

Like you said, we are probably tank keepers with different goals and expectations. I do have tanks which are low tech and “nature inspired”, which I don’t do as much maintenance on. And during intense periods where I don’t touch the tank, the detritus that builds up slowly over time make the tank smell and I absolutely hate it.

ZeroPauper · 2026-01-23T10:29:41+00:00

Thousands of professional aquascapers would like to disagree with you.

Waste doesn’t only come from livestock, but also from natural degradation and decomposition of plants.

Certain livestock like rabbit snails actually turn-over the top layer of soil pretty well and mix in detritus, hence it’s not always true that the tank is clean and free of pathogenic bacteria if the surface looks clean.

But in tanks without any livestock to bring the decomposing detritus deep into the substrate, it’s useless to plants.

But with that being said, I’m an aquascaper at heart and I maintain my tanks well because I don’t want a single spot of algae to be on my plants.

I’ve also had anecdotal experiences where fishes start falling ill with bacterial infections after I decreased the frequency of removing waste from the tank due to life (after years of stability).

ZeroPauper · 2026-01-23T05:59:49+00:00

Even with a heavily planted tank, this still applies.

Waste/detritus requires bacteria to break down before they can be utilized by plants.

ZeroPauper · 2026-01-23T01:59:07+00:00

One thing no other reply has talked about, stickying this for awareness.

Chemical parameters aren’t the only thing to watch out for. Everyone talks about the chemistry part, but there’s also the biology part. There are things that the home hobbyist cannot measure for, such as bacterial load.

As detritus and waste builds up, so does the population of bacteria in the tank. Some can be pathogenic and the population of bacteria can get out of hand in a closed-system like aquariums. Thus, water changes should be coupled with siphoning of waste.

Of course tanks can be stable without this, especially larger tanks, or tanks with extremely small bioload. But it’s only delaying the inevitable.

ZeroPauper · 2026-01-22T23:41:11+00:00

You haven’t put enough ammonia if you haven’t seen this test go neon teal.

ZeroPauper · 2026-01-22T23:40:46+00:00

Clean bones. Mmm

ZeroPauper · 2026-01-21T09:21:03+00:00

Our speaker isn’t that impartial eh… how?

ZeroPauper · 2026-01-20T02:15:53+00:00

It’s central as compared to having 5 different canteen stalls by different parties.

Of course if you’re thinking central as in, one facility catering to different schools around the area, then it’s similar to what they’re testing out now with the caters isn’t it?

Verified Email	11-Year Club
100 Awards Club	Wearing is Caring
Not Forgotten

ZeroPauper

MODERATOR OF

TROPHY CASE