# CO2 & Rummynose



## CeeJay (18 Jul 2010)

Hi all.
Having just changed my CO2 bottle, I always have to tweak my needle valve when I fit a new bottle.
Tonight I observed something weird.
During the last hour of the lighting period, (CO2 had been off for an hour at this stage), all my Rummynose tetras went to the bottom near the substrate and were not swimming around and looking stressed. IME this tells me that I've cranked the CO2 too high   .
However, tonight is the first time I've noticed this, when the lights went out, the Rummynose started swimming around as if nothing was wrong  :?. 
How mad is that? The CO2 doesn't just disappear when you turn the lights off  :?.
Anyone have an explanation for this behaviour?


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## Dolly Sprint 16v (18 Jul 2010)

Chris 

My rummies do the same - the majority of the time they are hidding in the plants and near to the bottom, half way through the lighting period - out they come swimming in the flow then disappear again, feeding time they are out in full force. My tank is heavily planted so plenty of places to hide. My personnel view regarding your Co2 - if they were suffering from a lack of o2 they would be high up the water column and maybe sub surface gasping for air.

Note: I have stated in previous threads that I think rummies are not a showy fish - might be different in a tank that has limit amount of plants - plenty of hardscape rather than a jungle of plants.

Regards
Paul.


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## CeeJay (18 Jul 2010)

Hi Paul.

Thanks for that.


			
				Flyfisherman said:
			
		

> if they were suffering from a lack of o2 they would be high up the water column and maybe sub surface gasping for air.


This is what I thought. But I have never seen mine up at the surface.
Looks like I have been misinterpreting what the fish are telling me   
I will keep a close eye on things tonight to see if I can suss out why their behaviour changes 1 hour before lights out  :? . I had thought that would be when CO2 was at it's max in the water column, so I put 2 and 2 together and got 5 .
Will keep you posted if I discover anything new.


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## stevec (18 Jul 2010)

my rummies only shoal together in the flow of the koralia when the lights are out....the rest of the time they are hanging around the bottom half of the tank not shoaling


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## CeeJay (18 Jul 2010)

Hi stevec

Mine were about half inch above the substrate.
However, tonight they were out and about as usual and nothing's changed in the tank.
How strange  :?
Obviously, not CO2 related


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## Anonymous (19 Jul 2010)

They don't like high light levels ... I keep them in my low light heavily planted tank and they are fine.
So what you have to do is either lower the lights, provide them cover in your tank when the lights are on or move them in a low light environment.


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## CeeJay (19 Jul 2010)

Hi clonitza

Well that sort of makes sense. Although these fish have been in this tank for 14 months now   .
What I do see is that the lights are on for 3 hours before feeding time and they are always out and about, swimming backwards and forwards across the width of the tank. Anyone goes near the tank and they think it's feeding time. After they are fed they seem to calm down. It's just that they calmed down a bit too much the other night  :?


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## Dolly Sprint 16v (19 Jul 2010)

clonitza said:
			
		

> They don't like high light levels ... I keep them in my low light heavily planted tank and they are fine.
> So what you have to do is either lower the lights, provide them cover in your tank when the lights are on or move them in a low light environment.




hi all.
Mine never seem to come of the bottom until its feeding time, but then they only go to mid water, I will have to keep my eye on mine them, I have one set of light that come on @ 16:00 followed by another set @17:00, the latter set go off at 21:00 and first set off at 20:00 - I will seem if there is more activity between 16:00 - 17:00 than 17:30 - 21:00 and 21:00 - 22:00 and post the results.

Regards
Paul.


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## CeeJay (19 Jul 2010)

Thanks Paul.
I'd be curious to hear your observations.
After all my fussing, and an upward tweak of my CO2, their behaviour is back to 'normal' tonight.
How odd that the strange behaviour was just for one night  :?


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## CeeJay (19 Jul 2010)

Forgot to mention, mine actually go to the surface for their grub  :?


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## Burnleygaz (19 Jul 2010)

I dont have rummynose tetras , but my tets go into hiding/stay low for quite some time if i have my hands in the tank for a while (trimming , water changing etc) which i presume is because they are getting spooked. might just be something similar. 

(also i always train my fish to feed from my hand , so i dont really understand it myself either )


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## kizkiz (20 Jul 2010)

I have a small shoal of 60 odd rummy nose in my 6ft tank
It's pretty heavily planted and well lit, but they shoal around the centre of the tank, mid level all day. Always out and about in the most open and well lit part of the tank.
They only hide in the plants, lower down, when the lights go out


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