I moved my 1.5 year-old bristlenose to a newly setup C02 tank yesterday and he has been happily munching on brown algae for the past 30 hours but a few hours ago I noticed some odd behavior where he was lying upside down under some driftwood "unstuck". I've never seen him do this before so I started to do some research and have read in a few places online that plecostomus don't like C02. But perhaps he has overeaten (previous tank didn't have much algae), or is just adjusting to new environment? The minute I nudge him he scurries off. Any insight here appreciated, do not want to risk losing him. Tank is 25 gallons, pH 7.0, KH 6, GH 7, ammonia 0, nitrite 0, water temperature 79f. He is the only fish in it at the moment.

Not sure about co2 since I don't have it but my bristlenose frequently display the same behabiour. I think they are rasping on my wood and go to sleep. When I disturb them they jump and go on about their business

What happens when you disturb yours during this behaviour?
Carol

Yea sounds like normal behavior, bn have funny personalities I'll tell u that lol

hrmmm, there are two issues that you need to look at. Firstly, Is the conc of CO2 too high? Now this is nothing to do with the amount of oxygen in the water, this is to do with the conc of CO2. If the concentration of CO2 is too high then no matter how hard the fish 'breathe' they can not get rid of the CO2 in their blood. Think about what happens if you pull the covers over your head, the conc of CO2 in the air goes up and no matter how hard you breathe you are still short of air.

the second is just the odd behaviour they have of sleeping like that. silly things they are

I learnt that one the hard way.

I now have a trio of peps in my CO2 tank and they look like they are gearing up to breed so YAY!

Thank you all so much for the feedback and to put my mind at ease a little. He (though after looking around a bit here I suspect he might be a she!) was very active overnight and seems fine this a.m. so I am very hopeful that all is OK. Like yours Carol, when I disturbed his "sleep" he scurried off to a hiding place. Doug, will keep a close eye and also get a drop checker or something to verify the concentration of CO2. It is metered with a pH controller but you can never be too sure.

So grateful for this forum and thanks again for your responses.

Lauri

to figure out the co2 conc you need to know the pH and the KH as these two things interact to influence the CO2 conc.

use this table to help figure out the CO2 conc in your tank

http://www.aquarticles.com/articles/plants/Podio_CO2_KH_PH_Chart.html -

CO2: KH/PH Chart
By Giancarlo Podio
Aquarticles.com