# co2 kill fish ??



## lord or the red belly (Aug 7, 2005)

hi ive been reading the fourum and i cant seem to find the answer to my question in my head 
ive tried for many months to grow pants in my tank it used to be full if rbps but ive converted it to trops again now it seems to me to make plants go then you need good lights which i have and co2 but fish need oxygen in order to live but if you put co2 then yes it will feed the plants but wont it kill the fish 
or do you run an air pump as well as running the co2 system ???

can any one help me 
thankyou phil


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## Ex0dus (Jun 29, 2005)

lord or the red belly said:


> hi ive been reading the fourum and i cant seem to find the answer to my question in my head
> ive tried for many months to grow pants in my tank it used to be full if rbps but ive converted it to trops again now it seems to me to make plants go then you need good lights which i have and co2 but fish need oxygen in order to live but if you put co2 then yes it will feed the plants but wont it kill the fish
> or do you run an air pump as well as running the co2 system ???
> 
> ...


you dont run air pumps you monitor the co2 allowed in your tank and keep it @ 20-20ppm max.


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## Gumby (Aug 13, 2004)

Ex0dus said:


> hi ive been reading the fourum and i cant seem to find the answer to my question in my head
> ive tried for many months to grow pants in my tank it used to be full if rbps but ive converted it to trops again now it seems to me to make plants go then you need good lights which i have and co2 but fish need oxygen in order to live but if you put co2 then yes it will feed the plants but wont it kill the fish
> or do you run an air pump as well as running the co2 system ???
> 
> ...


you dont run air pumps you monitor the co2 allowed in your tank and keep it @ 20-20ppm max.
[/quote]

Actually a lot of people run their CO2 as high as 50-70ppm without problem.

In short though, yeah, CO2 can kill fish. You definately need to keep an eye on the fish. You can tell if they are under CO2 stress if they are gasping at the surface or breathing heavily. If you KH is not high enough, CO2 can drop your pH very quickly which will also kill fish.


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## spree_rider (Mar 20, 2004)

tom bar claimed to have his co2 up to 120ppm with only his shrimp dying and the fish still doing quite fine.
remember co2 and oxygen dont limit eachother in otherwords you can have alot of co2 and alot of oxygen at the same time, adding more co2 does not push the oxyen out of the water.


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## harrykaa (Jan 10, 2005)

spree_rider said:


> tom bar claimed to have his co2 up to 120ppm with only his shrimp dying and the fish still doing quite fine.
> remember co2 and oxygen dont limit eachother in otherwords you can have alot of co2 and alot of oxygen at the same time, adding more co2 does not push the oxyen out of the water.


Actually the more you have CO2 in water, the less you will have O2 in that water. The total concentration of those gases together is quite stable, and depends on the pH and also the temperature.
Also aeration and strong surface agitation balances the concentrations of these gases.

Regrads,


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## DiPpY eGgS (Mar 6, 2005)

Not trying to argue, but I have had my CO2 @ 55ppm with like 75 fish in my tank for over a month, and not 1 suffered, or died, or had trouble breathing

I have never lost a fish or a shrimp due to high CO2 levels.. I never had a fish gasp at the top of the tank, or anything of the sort.

30ppm is the going recommended level, if you are going that route. I keep mine at 35-40 when I check it, no prob. at all

Also, when you have lots of CO2 in the water, the plants take it in, and exhale oxygen. When the water gets saturated with oxygen from this process, the oxygen that the plants create form bubbles under the leaves, (pearling) because there is already too much of it in the water. 
These 'air bubbles' will just float to the surface.. no where else to go.


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## bob351 (Oct 23, 2005)

listen to dippyeggs he seems to now all about plants and water chemestry from the looks of his tanks


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## harrykaa (Jan 10, 2005)

DiPpY eGgS said:


> I have had my CO2 @ 55ppm with like 75 fish in my tank for over a month, and not 1 suffered, or died, or had trouble breathing


Hi,

Yes it seems that 30 ppm or even 55 ppm is nowhere near the limit, at least for Piranhas. You have a Serra sanchezi if I remember correctly.

Regards,


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## DiPpY eGgS (Mar 6, 2005)

harrykaa said:


> I have had my CO2 @ 55ppm with like 75 fish in my tank for over a month, and not 1 suffered, or died, or had trouble breathing


Hi,

Yes it seems that 30 ppm or even 55 ppm is nowhere near the limit, at least for Piranhas. You have a Serra sanchezi if I remember correctly.

Regards,
[/quote]

yeah, there is a limit, but it really has to be up there, with no one watching, or checking the tank.. like a problem happening while on vacation or some misfortune like that


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