The Significance of pH for cichlds

[duanes]

I have on occasion, heard aquarists poo poo the significance, and relevance of a waters pH.

A pH of 4, common in black water rivers of South America, such as the Rio Orinoco, Rio Negro or Atabapo, where cichlids such as Cichla (peacock bass), many newly discovered pike, or Geophagine cichlids, or even common Heros species (such severums) come waters that are 400 times more acidic, than a pH of 8, in the rift lakes of Africa, where Malawi, or Tanganyika cichlids, where mbuna, Tropheus, and Nimbochromis are found, or…… in high pH waters in Central America where species such as Parachromis, Amatitlania, and Vieja exist.

Each 10th,”lower” in the pH scale, it is 10 times more acidic than the previous tenth (example 7.6, is ten times more acidic than 7.5).

What this might mean to a cichlid keeper, is that if trying to keep Severums in the same tank with mbuna (depending of the aquarists water parameters) means one of the species, may be healthy, while the other may come down with Hole in the head disease (HITH).

The reason is because bacteria have evolved to live specific pH ranges, and are very sensitive to the pH in water, that higher animals like fish are normally less superficially sensitive to.

There are very different bacteria evolved to live in different pH water.

And fish have normal resistance to only certain bacteria in the waters where they have evolved, but not to bacteria where they have not evolved.

 

[duanes]

Another example may be Ram cichlids that live in pH 5 water, so if kept with Convict cichlids, evolved to live in pH 7.5, it may be difficult to keep them healthy in such opposing waters.


The cons come from water hat is 250 times more basic (less acidic) than the soft, pH 5 water Rams have evolved to exist in, so the more sensitive Rams often suffer.

Some suggest, that a breeder in a certain city, will use the same tap water that the aquarist have.

But do they?

Many breeders will alter their water to fit the species they breed, by cutting their tap water, with RO if it is too hard, or slightly acidifying the water their cichlids spawn in, to better suit those certain species of cichlids natural needs.

Or if water is too soft, and low in pH, they may add mineral salts to there tap water that is lacking in comparison to the waters, for Rift lake species.

And/or breeders may do 50% to 80% water changes per day, to assure productivity, and keep the bacterial load down. But when the cichlids eventually end up in an aquarists tank, where a 25% or 50% water change per week is common, things go haywire.
All these factors weigh in to the health cichlids, in an aquarists tank.

If however, the aquarist is satisfied in keeping bread and butter fish, that have been raised to tolerate average pH around 7, like average tap water and its conditions, this is great.

But
if one aspires to keep more exotic or finicky, or wild caught species, those that may need specific water parameters, getting out that “chemists hat”, may be what may be required to keep those species healthy.

 

[neutrino]

if one aspires to keep more exotic or finicky, or wild caught species, those that may need specific water parameters, getting out that “chemists hat”, may be what may be required to keep those species healthy.

Agree. And this is where experience and knowledge comes in, whether personal or through doing a little research, as well as not being stuck on stereotypes, including the notion that all SA fish live in soft, warm, acidic water-- they don't. So, for example just because a particular type or species can be found in black water, doesn't necessarily mean it can only live in a soft water, low pH tank. Sometimes the fish we think of this way have a wider distribution than people think, live in more varied conditions than people think, their ancestry is more varied than we think, and through some combination of these or other physiological reasons are more adaptable than we might think. In addition, the actual collection location of a particular population may be listed as this or that river, while they're actually collected upstream and in different conditions-- as an example of this, see the comment from the link below from importer Kevin@TUIC regarding Heros sp, rotkeil, where he says (or strongly hints) that, similar to some other fish, their actual location is a "small, unnamed tributary" rather than the Rio Nanay, as commonly listed. In other words, not all fish come from exactly where we think they do and the water conditions in their actual location can be different from the main river to which they're associated.

On the other hand-- there certainly are sensitive, black water "obligate" species that you don't want to keep in hard-ish, higher pH water unless you want to have issues with them or shorten their lifespans. SO-- when the odd one or two say they're "thinking outside the box" and keeping X sensitive, timid, soft water species in conditions most everyone experienced with them says will cause issues-- probably a bad idea to pay attention to the one or two. On the other hand, when many have successfully kept and bred a particular fish in more generalized conditions, it can be narrow-minded to insist they're wrong about how adaptable they can be. So, for example, I can tell you from years keeping and breeding them that Geophagus pyrocephalus (red head tapajos) don't mind moderate harness or pH in the higher 7s and, having kept them for years and raised hundreds, including wild, I can tell you that Heros sp. rotkeil also do not mind moderate hardness or pH anywhere in the 7s, including the higher 7s. On the other hand, I've found Guianacara less adaptable to high pH and (specifically carbonate) hardness.

Post in thread 'Is Heros Rotkeil hybrid?'

Sep 19, 2021

Always a conspiracy theory with this species lol

Heros cf. efasciatus 'Rotkeil' is a naturally occurring species that can and has been wild collected for a nearly 2 decades from a section along the Rio Nanay in Peru. Multiple exporters out of Peru offer this species regularly. They are not a secret species but the issue is that the local fisherman and the exporters do not know them by 'rotkeil' they go by another local name. Sounds weird right? Nope, it is super common in the industry. Remember, these are not scientists...

• Kevin@TUIC

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[RD.]

Bingo

Thread 'South American habitat-- river types'

Nov 15, 2019

When it comes to water conditions, too much credence is often given to clichés of region as opposed to specific habitats. This includes the notion that African = high pH, hard water and South America = low pH, soft water. Some understand the mistake in this and know that: a) not all African aquatic habitat is highly mineralized, high pH and b) not all SA habitat is low pH and soft water. However, some who understand this still conceptualize SA water conditions as divided along geographic/regional lines that inadequately account for the variations in habitat within the same region...

• neutrino
• Replies: 31
• Forum: Central and South American Cichlids

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For many years I believed that ALL discus types, including all of the various domestic strains, only truly thrived if kept in low pH water, and fed beefheart.

Wrong.

 

[neutrino]

bacteria have evolved to live specific pH ranges, and are very sensitive to the pH in water, that higher animals like fish are normally less superficially sensitive to.

There are very different bacteria evolved to live in different pH water.

And fish have normal resistance to only certain bacteria in the waters where they have evolved, but not to bacteria where they have not evolved.

I'm glad you point this out regarding pH and bacteria. We commonly say that black water habitat is "low in bacteria." A convenient shorthand, but not quite correct. It would be more accurate to say the bacteria (and fungi) populations of SA black water rivers is different, adapted to these low pH, low mineral, tannin loaded waterways and mainly occupied with breaking down leaf litter and similar matter, while some of them appear to play a role in helping fish adapt to what are actually extreme conditions for freshwater fish.

Important role of endogenous microbial symbionts of fish gills in the challenging but highly biodiverse Amazonian blackwaters - PMC

Amazonian blackwaters are extremely biodiverse systems containing some of Earth’s most naturally acidic, dissolved organic carbon -rich and ion‐poor waters. Physiological adaptations of fish facing these ionoregulatory challenges are unresolved but ...

pmc.ncbi.nlm.nih.gov

 

[neutrino]

It's easy to assume we're doing blackwater species a favor by trying to replicate their native habitat, without realizing there's more to it than super soft, super low pH water. Among the points to note in the article linked below is this, which illuminates one reason some "blackwater" fish are more adaptable than some think.

Some species, such as the Sardinhas, Triportheus albus, which can be found across white, clear and blackwater environments, show phenotypic plasticity, meaning elements of their physiology change between individuals across these different environments.

But that's not my main point here, which is more to do with the illusion that we've reproduced their 'natural' habitat when we may have fallen far short, meaning our "blackwater tank" can be more removed from native conditions than we think.

A blackwater breakdown

The blackwater biotope is all the rage in hobby circles, but is there more to it than just staining the water? Chris Sergeant explores the dark and murky waters.

www.practicalfishkeeping.co.uk

 

[neutrino]

I've read several articles now on the dissolved organics and submerged wood and leaf litter microbes in Amazon region, including blackwater rivers. This appears to be an ongoing subject of research with much more to discover, so all I'm suggesting is there's more to it than some think and we have a lot to learn here. A sample of what I've found:

On the leaf litter community of the Amazonian blackwater stream Tarumazinho | Journal of Tropical Ecology | Cambridge Core

On the leaf litter community of the Amazonian blackwater stream Tarumazinho - Volume 2 Issue 1

www.cambridge.org

Previous studies concluded that these acid waters were of very low productivity and held impoverished faunas. However, this study showed that leaf litter banks held a diverse aquatic community of unexpectedly high biomass... The macrofauna was dominated by fish and shrimps. From an examination of gut contents a food web was produced. Primary consumers were found to take mainly detritus and fungi...

 

[jjohnwm]

A pH of 4, common in black water rivers of South America, such as the Rio Orinoco, Rio Negro or Atabapo, where cichlids such as Cichla (peacock bass), many newly discovered pike, or Geophagine cichlids, or even common Heros species (such severums) come waters that are 400 times more acidic, than a pH of 8, in the rift lakes of Africa, where Malawi, or Tanganyika cichlids, where mbuna, Tropheus, and Nimbochromis are found, or…… in high pH waters in Central America where species such as Parachromis, Amatitlania, and Vieja exist.

Each 10th,”lower” in the pH scale, it is 10 times more acidic than the previous tenth (example 7.6, is ten times more acidic than 7.5).

I'm certainly no chemist, and I'm having a bit of a hard time with this stuff.

Firstly...I am assuming you meant that pH7.5 is 10x more acidic than pH7.6, rather than the reverse as stated?

Okay, if that's correct...then pH4 is much more than merely 400x as acidic as pH8. If the above explanation is used, then pH4 is 10 to the 40th power times as acidic as pH8. Four full points, 40 tenths...a 1 with 40 zeros after it?!? Is my interpretation incorrect?

I think it's accepted that any species of fish, whether it prefers lower or higher pH levels, is certainly capable of living perfectly well...not merely tolerating, but actually thriving...in a range of pH numbers. The ranges for various species may be quite different, may not even overlap, but expressing it this way...this river is a million times more acidic than that one (that's only 9 zeros after the 1, rather than a staggering 40...i.e. the difference between pH7.0 and pH7.9, or between pH4.0 and pH4.9) sounds almost like marketing-speak, making the difference seem as huge and intimidating as possible. But, it can be interpreted and stated a different way as well, i.e. this species of fish can tolerate this range of pH, which increases a million times from top to bottom of its range...so it seems like a testament to the adaptability of the fish...or the bacteria...to changes in pH.

Now...what's all this about beef heart for discus? I mean, everybody has known for years that...well, you get the idea.

 

[duanes]

As pH numbers get higher, pH levels get more basic, as they get lower, pH levels get more acidic
So 7.5, is more acidic, than 7.6..

 

[duanes]

One of my points in this soliloquy.
Is that there are always resonable alternatives availble for waterever water parameters we are dealt with.
One of the species I always liked were Heros severus, but with my high pH, hard water, keeping them was always a bit futile.
So instead, I kept these,