Disaster Tank

[fionah]

A few weeks ago I purchased 4 black tetras for my main 65 litre tank. At that point, I had a 4 honey gouramis, 3 corydoras, 3 white minnows.

Some fish developed white spot, so I treated it with raised temperatures and Protozin. The following week some fish got fungus, so I treated the tank with Myxazin.

Slowly the fish have started to die, and I am now only left with 1 white minnow and 2 corydoras.

I have been testing the water with my API master kit (and took water to LFS who confirmed same readings), and everything was fine apart from pH:
Ammonia 0
Nitrites 0
Nitrates 5-10
pH 6.4

Up until recently pH had been steady at around 7.4. I have now purchased some stones for the tank that is meant to slowly raise the pH.

The 2nd 30 litre tank is ok (pH steady at 7.4 as well) and the fish are fine (1 betta, a few neon tetras and gold barbs).

Not sure what to do with my main tank now. Should I strip it down and start again? The remaining 2 corys and white minnow look fine, so I could move them in to the 2nd tank. Or am I supposed to just leave them there to eventually die as well of who knows what. I'd rather not though as the two little corys were the first fish I ever bought when I first set up the tank in January.

The LFS suggested it's a problem with air fresheners in my lounge, though I haven't been using this, and there is nothing wrong with the 2nd tank that is also in the same room.

 

[WILDER]

What substate do you have in the tank.
Do you have any bogwood in your tank.
List everything you have in the tank as something lowering your ph.
What make is the test kit you use, check also its not out of date.
What your tap ph.
Don't do large water change till you know why your ph is lower than your tap reading.

 

[LauraFrog]

If you're using pH test strips, give up. They are total rubbish and will wildly swing from one end to the other with no accuracy. Buy a bottle of the liquid pH test, it's cheap and much, much more effective.

Are you sure the fish had fungus and not columnaris? It's called mouth fungus but it's actually bacterial. It's often misidentified as fungus but then fails to respond to anti fungal drugs because it needs antibiotics.

 

[fionah]

What substate do you have in the tank.
Do you have any bogwood in your tank.
List everything you have in the tank as something lowering your ph.
What make is the test kit you use, check also its not out of date.
What your tap ph.
Don't do large water change till you know why your ph is lower than your tap reading.

The substrate is sand
There is no bogwood in the tank (I took this out a few weeks ago as soon as I found that the pH had dropped)
There are some live plants in there
It is an API master test kit (liquid). The test results matched that of the LFS when I took the water in for a 2nd test.
The tap pH is approx 7.4

 

[WILDER]

Did you do large water changes after you removed the bogwood.
What type of stones are they.
Not wise to do large water changes when your tank ph is different from tap ph.

 

[fionah]

If you're using pH test strips, give up. They are total rubbish and will wildly swing from one end to the other with no accuracy. Buy a bottle of the liquid pH test, it's cheap and much, much more effective.

Are you sure the fish had fungus and not columnaris? It's called mouth fungus but it's actually bacterial. It's often misidentified as fungus but then fails to respond to anti fungal drugs because it needs antibiotics.

It is an API master test kit (liquid). The test results matched that of the LFS when I took the water in for a 2nd test.

I am not sure about the exact cause to be honest. All I know is that some of the fish had cotton wool growths so I treated it with Myxasin which seemed to clear the cotton wool. However, may of the fish have died suddenly with no apparent symptoms beforehand.

 

[WILDER]

If your ph is all of the place it making the fish ill.
You need a stable ph in tanks or fish can get ph shock if it changes fast.
I would take the stones out of the tank to get your ph stable.

Your tap ph is fine for the fish you keep in that tank.

Kept all them type of fish in a 7.4 ph and they were fine.
Never kept white minnows.

 

[fionah]

Did you do large water changes after you removed the bogwood.
What type of stones are they.
Not wise to do large water changes when your tank ph is different from tap ph.

The first time I noticed the low pH was a few weeks ago and it was reading at the lowest value (6.0). I removed the bogwood and did about 40% water change. This brought the pH up to 6.4. The pH has remained stable at about 6.4 since then (even after weekly 20%-30% water changes).

Up until these few weeks, the pH has always been consistently at 7.4. My 2nd tank is currently at 7.4 and there are no problems. The 2nd tank has the same sand and live plants.

I think they are limestones. The LFS said it would help increase the pH but so far it hasn't done so (after 2-3 weeks).

 

[WILDER]

Dosn't make sense to me something keeping your ph low if your tap ph is 7.4
I would do a thread in tropical discussion about your ph and see what other members come up with.
I would remove the stones if you are not sure what type they are.

 

[backtotropical]

Hi Fiona,

How often do you do water changes and how much water do you change each time? Infrequent water changes will cause the pH to drop.

Assuming this is the problem, I would suggest small regular water changes (say 10 - 15% every 2nd day) until the pH returns to normal.

Also, have you checked the pH of your tapwater recently? It may be the case that your water authority are doing some fiddling which would cause the pH to drop. Just a thought.

Limestone will increase the pH in the tank but it will happen slowly, probably a matter of months before you notice any difference.

Cheers

BTT

 

[WILDER]

Her water stats are fine that why it dosn't make sense.
Ammonia 0
Nitrites 0
Nitrates 5-10
pH 6.4

 

[fionah]

If it sounds like the pH is causing the fish to die, then would it be safe to move remaining 3 fish to the 2nd tank which has a higher stable pH? Perhaps I should just start again with the main tank or even get rid of it all together.

 

[WILDER]

There a big difference in ph you would be climatising them for ages.
I would remove the rocks for now if I was you then keep testing your water.

 

[backtotropical]

If it sounds like the pH is causing the fish to die, then would it be safe to move remaining 3 fish to the 2nd tank which has a higher stable pH? Perhaps I should just start again with the main tank or even get rid of it all together.

Don't do that Fiona. It should be a simple case of regular water changes to raise the pH back up and a bit of detective work to find out what caused it to fall.

Do you inject CO2 into the tank for the plants by any chance?

 

[fionah]

Hi Fiona,

How often do you do water changes and how much water do you change each time? Infrequent water changes will cause the pH to drop.

Assuming this is the problem, I would suggest small regular water changes (say 10 - 15% every 2nd day) until the pH returns to normal.

Also, have you checked the pH of your tapwater recently? It may be the case that your water authority are doing some fiddling which would cause the pH to drop. Just a thought.

Limestone will increase the pH in the tank but it will happen slowly, probably a matter of months before you notice any difference.

Cheers

BTT

I change about 20-30% every week.
The tap water is fine at 7.4 and is being used in the 2nd tank with no problems.
I didn't realise it would take that long to increase pH with limestones!