Fish Dieing Rapidly

[OhMyFish]

Linking to my last post at [URL="http/www.fishforums.net/content-page/255...Wrong-/page/20/"]http/www.fishforums.net/content-page/255...Wrong-/page/20/[/URL]

"I thought when I next reported in, there would be more progress. Well, yes and a big NO!

First, this morning I checked the nitrites. If they were going up, then I intended to squeeze in another 50% water exchange. Well...they were at .25! Since prior readings had been .75, .5, .37, I thought ok...safe until this evening.

This evening, DH goes downstairs and notices a fish is dead and another is dying. Both are blood fin tetras. By the time I get down the steps, a 2nd blood fin has died. Within minutes 5 blood fins were dead and one not doing so well. DH takes the dead fish and a water sample to PetCo for testing. DS is going berserk as the fish have become his pets. Albino cory isn't moving but is alive.

DH called me from PetCo. The "only" thing wrong is that the pH level is so low that the fish are burning up. I immediately do a 70% water change and test the water after about 10 minutes. ph level is 6.8. As soon as I begin lowering the water, the albino and emerald green cories become very active. The silver-tips and neon are doing well. The x-ray seems ok. The blood fin is struggling but alive.

2 1/2 hours later, DS tests the ph and it is 6.4. The x-ray fish' tail fin is deterorating...looks a bit "feathery." The albino cory is hiding, not moving much again. The blood fin is hiding under a leaf (looks like the leaf is keeping him from floating to the top but he appears alive).

Ok...so, what is causing the ph to drop so dramatically?

Throughout the ammonia problem, the ph has been very low--off the chart. Ammonia is now 0 and nitrites are .25.

DH brought home some chemical to raise the pH but I've not used it as yet.

What to do...what to do... "

 

[LauraFrog]

Acidification is common in tanks running on undergravels if rotting detritus or a dead fish or something gets under the undergravel plate? Are you running an undergravel?

Clean the filter, get rid of any rotting stuff in the sponges but don't touch the ceramics or the bioballs. Keep checking the pH. How low is it dropping and what is the lowest range on the test you have. Do you have the exact number it fell to?

The chemical to raise the pH is usually bicarb. It's not ideal. It will raise the pH but it doesn't get rid of the problem. Picture this: you take a bottle of hydrochloric acid (pH 2) and a bottle of bleach (pH 12). You mix equal quantities of them together. The resulting solution is neutral pH. But I still wouldn't ask a fish to live in it.

Go and buy oxyshells to 'stabilise' the pH. They do this by raising the hardness. Tetras don't like it but they will cope better with that than really, really acid water. It will work as an interim measure until you can work out why your water is acidifying.

 

[OhMyFish]

LauraFrog, thanks for replying.

This morning, the pH level was again off the chart (below 5 which is as low as my chart goes). DH did a 50% water change after first testing the tap water (pH 7.4) and the water after the conditioner is in (pH 7.2). Late this afternoon, I'll check the pH level and probably do a 50% water change again. Fortunately, no more dead fish this morning.

We are using an undergravel filter. There are no dead fish in the tank. (Yesterday, I removed them as they died.) I don't believe there is any decaying leaves, etc. under the gravel. DH removed the bamboo plant this morning. There is still the java fern in the tank, along with two "plastic? fish tank ornaments" we purchased at PetCo when we set up the tank. The gravel was also purchased at PetCo when we set up the tank.

Frankly, I don't know how to clean the filter. I guess I take off the container holding the carbon and rinse it? Won't that interfere with the ammonia level which we just got under control?

 

[OhMyFish]

pH readings 1 1/2 hours after the 50% water change is 6.4. In 90 minutes the pH has dropped .4! The ammonia, nitrite and nitrate are all at 0.

The bamboo plant was removed and not returned to the tank prior to the water change.

Looking under the undergravel filter (yeah, we can see the bottom of the tank!), it appears to be bacteria growth. There doesn't appear to be any decaying matter (like leaves from the prior ludgiwa which has been out of the tank for at least 2-3 weeks.

DH said when he added the new water, there was a lot of "stuff" coming up from the gravel. It has settled down now.

Should I vacuum the gravel? (I haven't done so in a couple of weeks.) Will that destroy the bacteria?