Fish outside their PH range.

[Tech]

Here's an open question to everyone.

Have you kept a fish outside of it's recommended PH range, if so how far, how well did the fish do, and what was your GH and KH?

 

[jwh]

Yes I have. You'll find a lot of farm raised fish would be kept outside their natural pH range, as they have acclimatised to the range typically found in the tap water in the area. I can't remember my exact numbers, or GH or KH. In many instances its probably more important to provide a stable pH than the actual pH within a range of say 6-8, sudden changes in pH is fatal.
Having said all this, I would always try and keep my fish as close to their natural range as possible, and would not try to keep e.g. african malawi's that want alkaline water with a pH of around 8, in water with a pH of 6.
Its always good to check the pH of the water the fish is being kept in, and how that relates to your tank water before you acquire it.

 

[Zhewitt04]

I asked this is a thread. Mine was concerning the ph range for a water softener but i learned from the responses that, its more about stability than exact ph range.

 

[duanes]

In many instances it depends on the species. If you have species endemic to rivers, streams, and small bodies of water, changes in pH are a fact of life, and the fish can be hardly phased. And some of those changes create triggers for breeding cycles.
If you have species that come from large stable bodies of water like the rift lakes of Africa, a bouncing, or out of range pH can be damaging. And although a pH out of norm may not show acute damage, it may create long term chronic damage over time.
How many times have we seen old oscars scarred heads from years in the wrong conditions. Lake Gatun in Panama has pH swing from lows in the 6s all the way up to mid 9s, and many fish fluorish.
And usually houses with water softeners, have an unsoftened tap somewhere in the house, that can be used for those fish which soft water was not part of their evolution.

 

[Pomatomus]

Yes I have. It is very common for fish that are bred in Florida to be used to our hard, alkaline water (e.g. neon tetras). I know several discus breeders that keep their fish at a pH of 7.5. I have also (accidentally) kept Lake Victoria flameback cichlids in a pH of 6.5. I would have been more concerned if they weren't happy and breeding!

 

[RD.]

I think that Duane really hit the nail on the head when he stated;

In many instances it depends on the species.

and

And although a pH out of norm may not show acute damage, it may create long term chronic damage over time.

For many species pH (or perhaps even more important TDS) values will be a non issue, for others it may break down their immune system over time allowing pathogens to advance, causing various illness/disease. I have found over the years that there are fish that thrive in my tap water conditions (cold - hard alkaline water) and others that don't fair so well over the long haul. I learned to avoid the latter, and focus more on the former.

 

[viejafish]

I too only keep fish that fit my water chemistry, never change my water chemistry to fit the fish.

I agree that it depends on the species on how adaptive they are to live and breed in water chemistry outside their natural range. In Florida fish farms, angels and many tetra species are raised and bred in hard water with no issues. Discus, despite having been domesticated for 50+ years, remain weak and impossible to breed in hard water. Oscar and Geophagus kept in hard water are vulnerable to HITH despite frequent WC. Hard water is not measured just by pH, but more representatively by KH, GH or Conductivity.

 

[Tech]

You'll find a lot of farm raised fish would be kept outside their natural pH range, as they have acclimatised to the range typically found in the tap water in the area.

Would they be acclimatized or selectively bred to be more tolerant to a higher PH?

I asked this is a thread. Mine was concerning the ph range for a water softener but i learned from the responses that, its more about stability than exact ph range.

This is likely true to a point and on a case by case basis. If you fall in the 6-8 range and are keeping hardy fish they should be fine. If your outside of that or keeping fish that are not tolerant to changes what is the result? Will they die unexpectedly and without cause, or just have constant illnesses?

For many species pH (or perhaps even more important TDS) values will be a non issue, for others it may break down their immune system over time allowing pathogens to advance, causing various illness/disease.

So which fish did not like your water and what's you tap water like? In theory alkaline water carries a higher bacterial count than acidic, did your fish just seem unable to keep their immune system up and die to things like hex?

 

[RD.]

Discus, despite having been domesticated for 50+ years, remain weak and impossible to breed in hard water.

Difficult to breed, yes, but certainly not weak when kept in hard water, not at all. I have seen many locals keeping many discus thriving long term in our local water, which is pH 8.0, and hard. No HITH, no Spiro/Hex, all good for many years. Typically the weaker discus are the Asian designer fish, which is due to genetics, not water conditions.

So which fish did not like your water and what's you tap water like? In theory alkaline water carries a higher bacterial count than acidic, did your fish just seem unable to keep their immune system up and die to things like hex?

A couple of examples ....... some species are more sensitive than others, such as some of the Satanoperca genus. These fish tend to come down with issues such as HITH, even in low stress environments, with low organics, nitrates typically at 5 ppm. As the fish mature, over a few years, some of them seem to develop a lower immune response, and become more susceptible to pathogens such as Spironucleus, which then triggers HITH outbreaks. NOT diet related, NOT nitrate/organics related - but these fish in their native environment would live in a more acidic water, where most of the bacteria in harder more alkaline water would not exist. This same native water also contains tannins, turpines, etc found in native leaves/bark etc that are known to have anti-bacterial properties. Remove the fish from that protective environment and introduce them to some of our local nasties and some fish don't hold up well over the long haul.

Even beyond pH/GH/KH/TDS etc, our local water in the winter is ice cold, 50F on a warm day coming out of the tap, and the gas created in our pipes in the winter months plays havoc with the slime coat of some species of SA fish, such as chocolate cichlids. (H. temporalis) So I no longer keep them either, as I don't have time to store water in vats etc.

 

[jwh]

Would they be acclimatized or selectively bred to be more tolerant to a higher PH?


They more than likely just get bred in that water, I have never heard of fish being selectively bred to endure a higher pH, I know this is sometimes claimed for brackish water fish, that they can be selectively bred to tolerate fresh water, but not in my experience.

I think viejafish makes a valid point that's it's easier to keep fish suited to your water parameters than changing your water parameters to suit your fish