Help - Fish Death

[Rupret]

Tonight, I had almost 10 fish, Rainbows and Columbian Tetras, die suddenly. My water chemistry is ok and within normal limits, nothing to cause this, except for my O2 level (from a cheap kit, albeit), which was low, low - well below 100%.

In the last week, I had angel fish that bred, but the angels ate the fry. The tank is well over due for a water change - I know bad, bad, bad tank owner. As of tonight the chemistry is ok - Nitrate on the high side, but that is it. Also, the water simply stinks and no previous adverse odor noted.

No other recent deaths in the tank. Tonight almost 10.

I have added an air pump, large bubbles, due to no air stones. I will complete a water change this weekend; won't be able to get to it sooner.

It is a 125 gallon planted tank, community fish (angels, tetras, rainbows, loaches, cory cats, plecos, etc.). Besides being over due for the water change, it has been a healthy tank for some time.

Any thoughts???

Thanks, Rupret.

 

[philipraposo198]

When you say water chemistry is okay and normal limits what do you mean?

What exactly are your readings. 10 fish just don't die without something really wrong taking place.

 

[Rupret]

I agree, ten fish just don't die.

pH: 6.8
ammonia: 0.0
nitrite: 0.0
nitrate: 80
phosphate: 0.25
KH: < 3 (I did three drops)
GH: 5-10 (drops of five)
O2: 5mg/l; 7.6 mg/l at current temp is 100% per test kit (80 degrees)

I have pH issues in my area, so 6.8, although not great is not bad (it can drop to 6.0 easily). KH and GH are normal for the tank. Nitrates are usually lower. Phosphate is lower than normal, usually about 0.5 to 1.0.

Any thoughts???

 

[philipraposo198]

nitrates are a bit high but dont see that as the culprit.

what kind of maint or additions to the tank is the last 2 weeks?

 

[Rupret]

No maintenance or additions, well except for the angel fish fry. Plants do well with no fertilizers. I have mild CO2 injection. I know the water change is long over due - been busy at work, assisting with recent tornadoes, and so on.

Nothing is standing out to me. I've had aquariums for decades, with few major ordeals. I did have a complete tank failure several years ago (chemistry was all off, pH, ammonia, nitrites, nitrates, and so on). Nothing recent.

O2 level appears low now, but that is it - that I see anyway, except for the odor, which is new.

 

[philipraposo198]

no weird fish behaviour? possible internal parasite?

 

[NanoJack]

When was your last water change?

 

[Rupret]

Water change is long over due. Not sure how long, but long over due. I am changing it this weekend. No new deaths since adding the air pump. Maybe, it is looking up.

Rupret.

 

[Sk3lly]

Good surface agitation is all you need to oxygenate a tank. Air pumps and bubblers are not needed.

Nitrates are high.

Co2 will make your pH fluctuate

 

[Brookster123]

You say you inject co2?? Who's to say they just didn't starve out overnight?

 

[Rupret]

CO2 is only on during peak lighting, thus off at night. No strange behavior, nitrates are high, but a water change today. Nothing abnormal for the tank. CO2 up and running for years, no new fish (except for the fry, which have been eaten), nothing else new. Water change was long over due, but just finished up today. I'll run a new chemistry panel.

Thanks everyone.

Rupret.