First fish death, but totaly unexplained

[ddaddy]

My tanks been running great for months, my stock included

6x Red Line Torpedo Barb
4x Silver Angel
2x Pictus Cat
1x Common Plec

This morning after feeding, i noticed one of the Torpedo's lying dead on the bottom.

First of all, i thought dead fish float obviously not.

I immediately tested my water, and all is perfect

Ammonia = 0
Nitrite = 0
Nitrate = 10
pH = 7

What could have caused this death?
Is there any more diagnosis i can do?

7 days ago, i added filter wool to my filer and used a dose of "Interpet Green Away" as i had green/cloudy water. This all cleared up within a day.

I haven't yet removed him from the tank, but will shortly.
The rest of the fish are keeping away from him.

Thanks

 

[Durbkat]

Did you notice anything on the barb like maybe looking like salt had been sprinkled on it or torn or battered fins or missing scales. And whats the tank size?

 

[ddaddy]

Tank size is 260l (Juwel vision 260)
Im always checking them for white spot (call me paranoid) and not noticed any.
I'll examine him further when i remove him.
All fins/scales look intact

 

[CFC]

Redline torpedo barbs like most Cyprinids are intollerent of low oxygen levels, when the algea dies off from the medication it gets pulled into the filter and adds to the rotting biological matter in the tank, this causes a massive bloom in the bacteria which break down this matter which in turn adds to the number of things using oxygen in the tank. If you have live plants then they will control this during the day as they produce oxygen but at night the plants become the problem as they switch from using CO2 to "breathe" and start also using the dissolved oxygen in the water, the oxygen levels then plummet and the weeker fish die.

 

[Durbkat]

Wait. Did you just notice he was dead or has he been in their for awhile? Because if you leave him in their to long it will mess your water up and whatever sickness he had your other fish might get it to when they try to eat him. Is their any white stuff coming out of its mouth like a fungus?

 

[ddaddy]

I think he must have died after feeding. He certainly wasnt dead last night, and not noticed when feeding this morning. He's lying at the very front of the tank, so i would have noticed him before feeding if he was dead already.

Could he have choked on his food?

I run a constant stream of air into the tank and have about 10 plants.

 

[Durbkat]

Maybe I don't know It's weird never heard of this before. Maybe he died of old age?

 

[ddaddy]

Maybe I don't know It's weird never heard of this before. Maybe he died of old age?

[snapback]909091[/snapback]​

Im afraid not, at around 2" i'd consider him young

 

[Durbkat]

Never mind. Anyone else have a possiblity?

 

[ddaddy]

I've just removed him, and I cant see anything wrong with him. It would be less frustrating if i had ammonia/nitrite spike so i knew what killed him.

All the other fish look fine.

I guess life goes on!

 

[CFC]

did no one see my above post?

 

[ddaddy]

Yes i did CFC, sorry, i assumed that as i had air lines pumping air into the tank 24hours a day it couldnt have been that. But i guess the fish must have just been very weak.

The extra bacteria you say that would have grown to break up the algea matter, will this die off as its no longer needed? Or will it be there forever eating away at the oxygen?

 

[CFC]

Bacteria works on a supply and demand basis, when there is a large influx of waste the bacteria colony multiplies rapidly to make use of this new food to process and then dies off again once the levels have returned to normal.

Airlines running into the tank doesnt mean you have more oxygen in the water, the only thing that gets oxygen into the tank is surface movement, the more surface movement you have the faster gas exchanges take place. But even then water can only hold a certain ammount of dissolved oxygen before it is over saturated and the oxygen forms into air bubbles which cling to surfaces within the tank and can no longer be used by the fish. Falling oxygen levels are a major cause of over night fish deaths particularly with fish that have high oxygen demands.

 

[ddaddy]

Thanks for your help. Is there anything i could have done to eliminate the problem? More surface movement purhaps (How can this be achieved).

Thanks again.

 

[Durbkat]

Do you have a power filter in the tank?