sensitivity to light?

[Jason]

I've noticed that recently my gold barbs are extremely sensitive to
light...when the light pops on, they get startled and literally fight
for positions under the plants to avoid the light. They have always
liked spaces in the shade, but seem to have become even more sensitive
after the latest water change, in which I might have added more
bicarbonate and bumped the pH from about 7.8 to 8.5.

I've read that gold barbs prefer pHs at 6-7 but I know that a stable pH
at a higher pH is better than an unstable lower one (and I can't use
phosphate-based buffers because of algae). The pH is now a bit higher
than it was before the pH change, which was about 7.8 back then.

Would a higher pH make them very skittish? (when the lights go off,
they just float around like they always do when the lights go out)

Thanks!
Jason

[Jim Anderson]

In article . com>,
says...
> I've noticed that recently my gold barbs are extremely sensitive to
> light...when the light pops on, they get startled and literally fight
> for positions under the plants to avoid the light. They have always
> liked spaces in the shade, but seem to have become even more sensitive
> after the latest water change, in which I might have added more
> bicarbonate and bumped the pH from about 7.8 to 8.5.
>
> I've read that gold barbs prefer pHs at 6-7 but I know that a stable pH
> at a higher pH is better than an unstable lower one (and I can't use
> phosphate-based buffers because of algae). The pH is now a bit higher
> than it was before the pH change, which was about 7.8 back then.
>
> Would a higher pH make them very skittish? (when the lights go off,
> they just float around like they always do when the lights go out)
>
> Thanks!
> Jason
>
>

Why are you changing water chem to be outside the range of your fish?

Adding bicarbs does not change pH, it changes kH which results in a pH
change as a symtom of the kH change.

You are lucky the fish survived such a drastic water chem swing during a
water change. They are probably in shock. That big a change should be
done gradually over a week or more.

--
Hope this helps.
Jim Anderson
( 8(|) To email me just pull my_finger

[Jason]

Actually, I misquoted the pH values. The pH before the water change was
around 7.6, and afterwards around 8.2. Is half a step that drastic? I
didn't change the chemistry so to speak--the "old" water pH had just
drifted downward after a couple of weeks due to natural acid production
in the system. The "new" water was just buffered completely.

The kH is indeed higher now because of the "fresh" unused bicarbonate.
Does a high kH itself create an inhospitable environment for the fish?

Last night, when the light turned off, the fish came out under the
shade and swam/drifted around normally in the tank. They seem to only
be acting weird when the light is on. Another thought was that fresher
water makes the light more intense since there are fewer particulates
to diffuse the light.

[Jim Anderson]

In article om>,
says...
> Actually, I misquoted the pH values. The pH before the water change was
> around 7.6, and afterwards around 8.2. Is half a step that drastic? I
> didn't change the chemistry so to speak--the "old" water pH had just
> drifted downward after a couple of weeks due to natural acid production
> in the system. The "new" water was just buffered completely.
>
> The kH is indeed higher now because of the "fresh" unused bicarbonate.
> Does a high kH itself create an inhospitable environment for the fish?
>
> Last night, when the light turned off, the fish came out under the
> shade and swam/drifted around normally in the tank. They seem to only
> be acting weird when the light is on. Another thought was that fresher
> water makes the light more intense since there are fewer particulates
> to diffuse the light.
>
>

The pH scale is logarithmic, which means, for example, that pH 5 is ten
times more acidic than pH 6. (What looks like a small change is
acctually a drastic change.)
....
The pH value of the water has an important influence on the way a fishes
body functions.
....
Apart from the effect of pH itself, there are important effects on the
toxicity of ammonia and nitrite with changing pH. Therefore you should
be particularly wary of attempting to change pH when either of these
waste products is detectable.

Quotes from <http://www.thetropicaltank.co.uk/ph.htm>

--
Hope this helps.
Jim Anderson
( 8(|) To email me just pull my_finger

[Mean_Chlorine]

Thusly "Jason" > Spake Unto All:

>Would a higher pH make them very skittish?

No. Many barbs (I have no experience with gold barbs, but close
relatives, e.g. bimaculatum, are in this group) are just naturally
retiring creatures who do not feel safe in strong light. Increasing
their numbers may offset their shyness, as may floating plants and
other schooling fish.

>Jason

[Jason]

Yes, my gold barbs are generally the type that will stay in the shade
if they can help it, but they seem especially terrified of the light
now. Even when it comes to feeding time, they'll stay in the shade
until they're sure I'm going to feed them, and even then, they grab the
food and run back under the plants. They went from a bit shy to
"terrified of the world" in one water change.