PH and osmosisregulation relationship

[waterboy]

Ok this might be a very stupid question but I have to ask.....Is there any relationship between PH and osmosisregulation. Can a fish stand a change of ph between 2 and 3 points? I know that fish can live in waters with a ph as low as 4 to 4.5. So why is that? And I know that there are swings of ph from that to 7.0 in the wild so why would this not be the case in the tank and why do the fish live. And why is it that fish are said to die with a large ph swing/crash.  Would this have to do with hard and soft water? Not PH. Thanks for you replies.  :wink:

[Obed]

Re: PH and osmosisregulation relationship

Not a stupid question at all. PH and hardness, while talked about a lot, is a subject that most of us do not know enough about.
You have correctly pointed out that ph and hardness are seperate issues and have differing effects on fish.
There are many common problems associated with ph and hardness and in nature there is a direct link between the two and that is why most people think of them as the same.
Osmosis is affected by both and once again is a reason lots of folks think of PH and hardness in the same way.
I have heard of people who wanted to increase the percentage of viable fry from fish like discus and angels and thought they were helping by lowering the ph of the water with additives like muratic acid that does indeed lower the ph but not the hardness and therefore did them selves no good.
Using something like an R/O unit to lower the hardness would allow the male to more easily fertilize the eggs because the eggs shell is then softer and more penetrable for a longer period of time and the success rate goes up.
Osmosis is higher in softer water which is one of the reasons that copper based meds become deadly instead of helpful natuaral amazon type tanks.
You are correct that deaths associated with ph swings are not a result (most often) of the ph swing itself, but more associated with the shift in hardness, but even here it is not the hardness or the ph but the secondary issues associated with those that is the actual cause of death, so ph or hardness swings should still be avoided.

[Mzungu]

Re: PH and osmosisregulation relationship

Are you asking about osmoregulation, or is osmosisregulation a separate process?

[waterboy]

Re: PH and osmosisregulation relationship

osmoregulation, sorry I got the name mis-spelled. I know that they regulate the salt through this process but wanted to know the corralation between ph and this process, if any and why. As I tend to think that hardness and softness plays a role in the death of fish besides ph swings. The thinking being maybe ions higher or lower in the water. I know that in the wild a fish will go through ph swings and not die but having a tank am always told not to have ph swings because it will kill the fish. If a fish in the wild can stand a 2,3 or even 4 point swing in ph then why not the tank in are homes? Also why is it that wild fish can stand a ph level down to 4.5 or even 4. I liked the explantion that Obed gave. But if you have something to add that would great, thanks and sorry about the confusion. :)

[Mzungu]

Re: PH and osmosisregulation relationship

Well, I like Obed's explanation as well! I really don't know much about this subject. I do want to ask you where you found that info about fish in the wild tolerating wild pH swings, though. Not that I'm discrediting you, not at all, hope it doesn't come out that way! I'm just always ready to read about things I don't know.

And when you say that wild fish stand a pH of 4.5 or even 4, do you mean species like discus, and some asian fish, like some of the betta species? Or are you linking the low pH to the pH swings? Just wondering, I think this is a good discussion to have.  

[PhishPhreek]

Re: PH and osmosisregulation relationship

Yes, many of the less well known species of bettas require a low pH
for an example see

wine-red betta

[waterboy]

Re: PH and osmosisregulation relationship

Well, I like Obed's explanation as well! I really don't know much about this subject. I do want to ask you where you found that info about fish in the wild tolerating wild pH swings, though. Not that I'm discrediting you, not at all, hope it doesn't come out that way! I'm just always ready to read about things I don't know.

And when you say that wild fish stand a pH of 4.5 or even 4, do you mean species like discus, and some asian fish, like some of the betta species? Or are you linking the low pH to the pH swings? Just wondering, I think this is a good discussion to have.  

Well, I can almost bet you that I know LESS than you. I have been reading article after article on this subject and I don't have a specific article to give but will try to locate the one that I read. I remember that some fish were there is acid rain have a low ph. Also were there is no rain the ph will drop then when it does rain the ph will rise very fast but the water is either soft or hard depending on the enviroment.

I think I read were if you put a fish from soft to hard water they have a hard time with osmoregulation and die. But do not die if going from a high ph to a lower ph with the same hard or soft water. As you can tell the info. is still sinking in.