Whats the big deal about soft water cichlids in hard water. Rant

[PYRU]

Did you even bother to read the previous posts regarding discus?

In general, and unless one is attempting to breed them, discus do NOT require RO, nor does one need to perform huge daily wc's to keep them healthy. That is nothing more than a myth, repeated on the internet until some consider it as fact. The vast majority of discus do just fine in regular tap water. This was all covered in detail, with pics included.

Relax....but no I didn't read. Im still getting used to the 10 post per page and not getting navigated to the latest. I was on the 1st page when I answered.

That's was meant as my opinion as well. I still say it's easier for the average person to go that route unless your lucky enough have good tap. I'm speaking from my own experiences and didn't realize its internet myth status. I'm not a discus expert by any means but remineralized ro is what worked for the ones I had.

 

[RD.]

I'm plenty relaxed, thanks. Millions of people world-wide raise discus in tap water, including commercial farms. I'm not referring to wild Heckels, or greens, that are clearly more sensitive than the various designer strains on the market. Just more internet misinformation, which at the end of the day helps no one.

 

[dan518]

Not been on much recently and only just come across this, great thread with some excellent points.
A hobbiest who takes the time to use ro water and keep a stable pH, tds, is probably a lot more fastidious about tank maintenance then some others. Does this mean his fish are healthier due to lowering his pH or just better tank maintenance.
I find it hard to believe that parts of the amazon are sterile. Fish have billions of bacteria in there digestive tract the same as humans, these are essential to digest food and even form part of our intelligence. If these bacteria can survive in the acidity of our stomach then I would assume (knowing what it's the mother of) others would have no problem surviving in the low pH of the water.

 

[Coryloach]

Of course the environment is not sterile. There are just different type of micro fauna than that of hard water, even the type of nitrifiers are different and so are the ones in our fish tanks subjected to different water parameters. Cichlids coming from that part of the world need adapting and building up an immune system towards hard water micro-organisms just like kids do. Keeping discus in bare sterile tanks at our homes isn't helping in breeding the best individuals either in my opinion.

 

[duanes]

I agree, it is the type bacteria that over millions of years, any fish evolves to live with, and have resistance to that are important.
Soft water fish will be resistant to soft water bacterial species, but may have little resistance to strains that flourish in water.
I would never suggest that soft water environments are sterile, or that even tap water is sterile (it has been disinfected in many cases) but it is by no means sterile.
Using disinfected and dechlorinated tap water for frequent water changes with soft water species however (if your water is hard) may help stave off some pathogens, those that less resistant fish may succumb to.
But as Coryloach just said, we aren't doing the fish any favors by trying to keep the the dregs of spawns, , if breeders were to keep only the resistant fish, and cull the less resistant ones (maybe as much as 70% or 80% of any spawn), our stock would be stronger in the long run.
This may not make short term economic sense, but long term,.....

 

[RD.]

Designer fish such as the domestic strains of discus, flowerhorn, etc-etc, are not bred for superior immune suppression, or longevity, they are bred for looks. The fact that many of these fancy designer strains are not long lived, makes perfect economical sense from the breeders/vendors standpoint.

 

[neutrino]

How can I put this without offending? A time scale of millions of years is almost meaningless to cichlid immunity in the present for several reasons.

One is how the immune system of bony fish works. It has two components: an innate (inherited) and adaptive (acquired) component. There are volumes upon volumes of science papers on this as it continues to be studied at the cellular and biochemical level. Inherited immunity means earlier generations pass on the ability to quickly recognize and fight pathogens that have been encountered before. Adaptive immunity is a system that recognizes newly encountered foreign invaders and then prepares a defense to fight them. Without citing some heavy, boring science paper, the simple proof of how well this works is the problem of invasive fish species, including cichlids, in various places. If cichlids, plecos, asian carp, snakeheads, pacu, etc. are happily living in foreign waters in the US, presumably encountering new pathogens or water mineral profiles, they probably can (and obviously do) handle unfamiliar pathogens in our tanks-- some of the issues have more to do with conditioning and acclimation, stresses we put them under, drug resistant superbugs, etc.

Cichlids did not invent their dual immune system. Cichlids fossils go back something like 46 million years, bony fish 400 million years.

Additional reasons millions of years ago has limited impact (especially in terms of limitations to immunity) on the present is that pathogens themselves are constantly adapting and most animals, including bony fish, adapt as well. It's not just that, but habitats change over centuries or thousands of years, sometimes decades. Cycles of climate, limnology, and geology dramatically change the landscape. Lakes and rivers come and go, change course, or see changes in chemistry. The watershed that is now the Amazon River flowed in the opposite direction before @ 10 million years ago, but other changes are much more recent. Pleistocene (ending @ 11,700 years ago) climate, flora, terrestrial fauna, and rivers themselves were different from the present and the current (Holocene) period has also been a period of change:
Geomorphology and evolution of the late Pleistocene to Holocene fluvial system in the south-eastern Llanos de Moxos, Bolivian Amazon

Seven paleochannel generations are identified. Significant changes in sinuosity, channel widths and river pattern are observed for the successive paleochannel generations. Our results clearly reflect at least three different geomorphic and hydrological periods in the evolution of the fluvial system since the late Pleistocene. Changes in discharge and sediment load may be controlled by combinations of two interrelated mechanisms: (i) spatial changes and re-organizations of the drainage network in the upper catchment, and/or (ii) climate changeswith their associated local to catchment-scale modifications in vegetation cover, and changes in discharge, inundation frequencies and magnitudes...

The particular stretch of a particular river that species "X" now inhabits and is adapted to may not have existed not so long ago, or if the location is the same, conditions may be different. Therefore, this 'species' is either much the same, and consequently adaptable to the former conditions, or it has changed in some way to accommodate the changed habitat. This would be a big subject all its own, but science now understands genetics to function more like software, with if/then logic acting on various triggers and environmental inputs, compared to the "blueprint" genetics of our former school days. This changes the model many have for how all of this works-- I'd go into it further, but this post is already long.

So, adaptation-- whether to microbes, habitat, climate, or water conditions-- is dynamic and ongoing. Individual species come and go as conditions change or as they colonize or retreat from various locations. Some will be more specialized to certain conditions than others, but because cichlids have existed for millions of years doesn't lock them into a written in stone state etched by millions of years. Among the adapting systems are immunity, feeding, and range of water tolerance, even while basic morphologies of some clades (geophagines and haplochromines, for example) have remained much the same for tens of millions of years.

Don't get me wrong, I'm not saying this means you can throw Lake Natron cichlids in a tank with discus, or you shouldn't quarantine, or that you can feed your Neetroplus an all guppy diet, or that temperatures too low or pH too low or too high can't depress immune function, but some go to the opposite extreme and either aren't aware of the natural range of certain groups (like discus), insist their comfort zone is more limited than it really is, or extrapolate the wrong conditions to the wrong species or population of a fish.

 

[neutrino]

...in other words, to sum up a lengthy post, the cichlid immune system goes back millions of years, but specific immune responses do not. Immune response is both flexible and adaptable. We should understand the distinction.

 

[Coryloach]

I personally find wild caught fish healthier and more robust fish than tank bred ones...They surely adapt, way better than the inbred by humans individuals.

 

[neutrino]

science now understands genetics to function more like software, with if/then logic acting on various triggers and environmental inputs, compared to the "blueprint" genetics of our former school days. This changes the model many have for how all of this works

Let me just add a point to clarify what this means. It means the model for many adaptations is not that of waiting thousands or millions of years for the right mutation to come along, they're already in the code (genetics), switching genes off or on in response to environmental inputs. There are a number of known functional examples of this, including familiar cichlid species. Here are two:
Diet predicts intestine length in Lake Tanganyika’scichlid fishes
The tropheus in your tank is not waiting on a mutation to adapt to your NLS pellets, the genetic mechanism already in place knows which genes to switch on or off. The system is millions of years old, the adaptation is not, the response happens quickly. Why is it there? Apparently tropheus have needed to and have been adapting to changing available food sources for a long time. They're not in an iron clad state reinforced by millions of years of stasis.

Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation

In several cichlid fish species (family Cichlidae), plasticity in different traits has been demonstrated: Meyer experimentally induced changes in the oral jaw morphology in the Neotropical cichlid Parachromis managuensis by feeding different diets [30], a similar procedure was followed by Bouton and coworkers using the African cichlid Neochromis greenwoodi [49]. The Lake Victoria cichlid Haplochromis pyrrhocephalus was almost driven to extinction by the upsurge of the introduced, predatory Nile perch in the 1980s, but was able to adapt morphologically to the new environmental conditions of high predatory pressure and eutrophication in only two decades

Theory is still catching up to recent genetic research in attempting to explain this, so you'll see varying hypotheses suggesting how this happens. Some invoke newer research than others. We can have our different outlooks, philosophies, or levels of knowledge to explain it, but however you slice it, this is a mechanism for adaptation that works quickly.