What are signs of CO2 poisoning?

[OhNo123]

I just started CO2 in my 10g shrimp tank. There are also guppies in there - they dont eat my shrimp. What are some signs of co2 poisoning i should look out for?

[Mgamer20o0]

well your not poisoning them you can suffocating them. so much co2 in the water it pushes out the o2 in the water. the signs are the same of lack of o2 in the water.

[OhNo123]

I see. I use a sponge filter in that tank.

[Mgamer20o0]

its really hard when doing diy to od co2. it takes someone really not paying attention to do something as stupid as put too much co2 in the water and kill the fish that way.....
(http://www.aquariacentral.com/forums/showthread.php?t=104182&highlight=co2)