is there such a thing as too much oxygen?

[jmajid]

So i have an indoor tank - and i have both a combo filter/pump and also now an extra airstone.
I was just wondering what the thoughts are about "too much" oxygen?
Is there such a thing?
Of course we all know about too little .... but what about too much?

thanks!

 

[MitchM]

Yes, you can have too much oxygen in certain situations.
If you overdose using hydrogen peroxide to fight cyanobacteria or trying to compensate for low oxygen during a power outage, you can kill your fish.
They can die from gas bubbles forming in their bloodstream.

 

[jmajid]

mitchm: thanks - so how "do we" know when is too much?
i dont have an oxygen meter - cant justify it -
are there symptoms of the "gas bubbles" we can look out for?

 

[MitchM]

If you're not dosing hydrogen peroxide, then you don't have anything to worry about.
If you are dosing, then be very careful of your dosing amounts and make sure you have good circulation or are doing spot treatments for cyano.

Without an oxygen meter, watch for signs of stress in your fish - fast, unusual swimming around for example.

There is no danger of over oxygenation with just strong water circulation. The gas concentrations in the water will equalize with the gas concentrations in whatever room the aquarium is in.

There are probably other signs of distress. Search online for "gas bubble disease in freshwater fish".

 

[jmajid]

mitchm: thanks for the info.
not using anything else - no peroxide - just wanted to know for education
also for future info in case i have any ailing fish, i wanted to know in case i use a pump / airstone without any valve control.

 

[MitchM]

You're welcome.

 

[JohnHuff]

Just a thought as I was browsing through the topics. People think of O2 is life giving but it's actually a highly reactive element and is toxic. It's not inert and too much of it will kill you!

 

[VanDiesil]

Airstones work by agitating the water surface with the bubbles for gas transfer and not actually put oxygen in to the water as such. Surface disturbance is the most important thing with regards to gas exchange, and one reason why in summer during bouts of extreme high air pressure and the lack of wind or rain that big oxygen crashes occur.