What type of freshwater fishes do not like lower ph?

[professorjimjam]

I have got a lot of free almond leaves ? for aquarium. I used 10 leaves for my 32 gallon and now the water is brown and I don’t have a ph tester but I read on internet that these leaves lower ph and May shock the fishes. Is that true?
How to I make sure that ph doesn’t get too low with these leaves and if I do a 50% water change will it give ph shock to my fishes?

I have guppies, bristlenoses, Congo spotted puffers and amazon puffers in the tank.

 

[TwoHedWlf]

50% water changes won't shock your fish if you do it regularly and your water change water is similar to your tank. If you've got something like a tank that's been neglected for long time and the water conditions have shifted hugely from your tap water, or some special conditions like high PH african tank, probably good to do a few smaller changes instead.

 

[professorjimjam]

Thank you TwoHedWlf

 

[Deadeye]

Almond leaves won’t have a major effect on the pH (might change it by 0.1 at most), but may release a lot of tannins (what you are seeing). Water has a very good buffering capacity.
Many of the Central American fish we keep, famously the cichlids, as well as guppies and other livebearers thrive at a more basic pH (7-8), with mollies even spending time in the ocean. They have been commercially bred for so long, their tolerance has widened a lot.
The most well known freshwater fish which thrive at high pH are the African rift lake cichlids. Some are found in waters with a pH of 9-10.

 

[professorjimjam]

Thank you very much Deadeye

 

[duanes]

Agree with Deadeye,
those few almond leave probably won't have changed your pH much at all, and by the lack of tea color in the water in your pic, its pretty obvious to me even the tannins they produced were minimal.
Because I use rain water in my tanks, and some comes directly off tropical trees, color gets fairly dark, and even the color in the pic below, does little to budge pH.

I did an experiment last year where I was adding half a dozen leaves to my tank every other day, for a month and couldn't get pH to budge.
If you are still worried there are pH strips that can be bought inexpensively at stores like big box hardware store that sell pool equipment that are reasonably accurate. The multiple tests like the one below, would be useful for a number of parameters, any aquarist needs to know.

Below the thread I posted last year


Experiment w Almond Leaves

 

[professorjimjam]

Thank you very much duanes

 

[duanes]

If your tap water has a very low buffering capacity (low alkalinity)(low GH and KH) it is possible pH could be influenced by such thing as leaf litter, and fish wastes, and even to plan a proper water change routine, so getting strips or a test kit, might be a very good thing keeping your fish.
Having tap water with a low buffering capacity often means that aquarist may need to do more frequent water changes than someone with a high alkalinity because the calcium in high alkalinity water keeps a tank more stable longer.
It would be advantageous to regularly monitor your tanks water, and even to know your tap water parameters, just as a general rule, to plan on proper stock, for your particular water conditions

 

[professorjimjam]

Thanks duanes my tap water has high KH and GH.

 

[duanes]

Since your water has a high GH and KH it has the general ability to resist change, so 10 almond leaves will have very little ability to alter its, pH, unless its been a long time between water changes. The buffering capacity provided by Gh and KH wanes as the metabolic processes in a tank build between water changes.

And in answer to the posed question, in the title of the post
its not so much what individual fish prefer, but for me, its about combining species from the geographic regions they have evolved to live in.
i.e. There are species of tetras,, puffers, and live bearers from both high pH, neutral and low pH regions.
Cardinal tetras and other type fish are endemic to Amazonian tannic inundated waters like in the chart below

But Central America high pH water also has species of Tetras, Chart below) here the species would be Astayanax or Roeboides

This is one of the reasons I try not to mix fish from certain geographic reasons, and sometimes certain rivers, or lakes.
Of course there are those waters that are generic (neutral pH) and with pH that changes seasonally Many common LFS, aquarium strain species are from, and completely adaptable when from those conditions.