# diy co2 bad for fish?



## almostaskater62 (Apr 28, 2007)

i have a diy co2 setup for my 10 gallon tank as of yesterday, and it's working fine, the bell thing is full and it seems to be diffusing

my question is, since i don't have aeration in the tank, is the co2 bad for the fish?
i do have a 20 gallon filter in the 10 gallon tank though, so i imagine that is aeration in itself


thanks


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## Laith (Sep 4, 2004)

Too high levels of CO2 can be bad for the fish (makes it difficult for them to expel CO2 from their bodies across their gills).

A sure sign of too high CO2 is the fish staying at the surface and gasping. But I doubt you can reach those levels with DIY CO2 and diffusing with a bell type "diffuser". A good habit to get into is to try to have a slight ripple of water across the surface. You loose some CO2 this way but it helps avoid too high levels. Others use aeration to help offgas any excess CO2 but I hate the things.  

And welcome to APC!


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## almostaskater62 (Apr 28, 2007)

the 20 gallon filter definitely has a ripple on the water
the gourami is the liveliest fish, which kinda made me nervous seeing as he breathes surface air
i have a guppy hovering at the surface, i dont really know what a fish's "gasp" looks like, but he looks normal
the platies are chillin at the bottom, not moving a huge amount, but not gasping either


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## bunty321jayne (Apr 17, 2007)

Why not treat yourself to a Co2 indicator - they're pretty inexpensive and will let you know if Co2 levels are getting too high / too low.


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## John N. (Dec 11, 2005)

I bet with DIY CO2 and your setup, the fish are fine. DIY CO2 doesn't usually produce harmful levels of CO2 since its hard to get up their in the first place with this type of rig.

-John N.


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