PH Shock - Osmoregulation

[vriesea]

To all:

While searching for and reading PH Shock ariticles I came across several conflicting or confusing statements.

1) PH Shock - There is no such thing as PH Shock it is really osmoregulation.
2) PH Shock - Pleco's are very impacted.
3) Ph Shock - Not a concern if less than 1.0 PH
4) PH Shock - Takes about 1 - 2 weeks to kill your fish.

I'm writing this because my PH is quite high (7.8 - 8.0) and I sometimes purchase plecos from vendors that have a PH in the 7.0 range. I've also had the occassional pleco that did not survive my quarentine tank.

What are your thoughts on PH Shock, should I be concerned, and where can I get better information.

Happy hobbying,
Vriesea

[Mike_Noren]

My opinion is that it is impossible to kill fish by moving it in any direction between clean waters with a pH anywhere in the range 6.5 to 9.5. The reason for this is that fish's blood is well-buffered against pH swings.

There's two caveats:
1) is that low pH is often associated with low salinity (low conductivity), while high pH is often associated with higher salinity/conductivity, and the osmotic chock is a killer. There is also a long-term (months) effect in that too high salinity/conductivity may cause kidney problems.

2) is that weakly toxic ammonium is converted to acutely toxic ammonia with rising pH, so a fish from dirty, low-pH water, may die from ammonia poisoning if pH is raised or the fish moved to higher pH water.

The importance of pH in my opinion lies in triggering spawning. I do not believe pH has any importance to the short-term or long-term well-being of fish as long as it is in the 6.5 - 9.5 interval and the accompanying salinity is acceptable to the fish.

Well, that's my view.

[apistomaster]

I have the same opinion as Mike.
I only change pH and hardness gradually as I prepare to spawn some species so once they are in their breeding tank the water chemistry is correct for that species. Many soft acid water fish may spawn at a higher pH and TDS but their eggs may not hatch and the fry may die from those eggs that somehow managed to hatch anyway. Many of the Tetras are like that.