Co2 bubbles, shy fish

[Tjoste]

Hi,
I have a 60p tank with 20 Ember tetras, where I run an in-tank co2 diffusor.

My Embers don't seem to like the bubbles from the diffusor very much. They spend the whole day inactive below some wood with moss, in the shadows.
Once the co2 turns off, 1h before the light goes off, they are very active. Swimming around and having a good time.

The co2 really ruins the experience, where the tank looks empty for the majority of the day.
Anyone with similar experience?
Would an inline diffusor help maybe?

Thank you!

 

[Tjoste]

Just found a similar thread where it was recommended to place the diffusor next to the inlet, so that the bubbles would go straight into the filter and get dissolved.
Im gonna try this tomorrow! My Oase filter burps enough air as it is, but lets see how it goes

 

[Kelvin12]

Strange, your not to high on the gas are you. Normally fish seem to like playing in the air bubble stream so I couldn't see why Co2 bubble would upset them unless the gas was running a bit to high and its irritating them.

Dirk

 

[Garuf]

It’s easy to test the theory, keep your co2 on for the last hour of lights and see if the behaviour persists.

 

[xZaiox]

Normally fish seem to like playing in the air bubble stream

I now use an in-line diffuser, so I don't have that in-tank bubble stream from one location, but when I did used to use an in-tank diffuser a few of my fish would do this - the gouramis were especially interested in the bubbles, I found it pretty funny

Strange, your not to high on the gas are you.

I'm also going to echo this question @Tjoste - fish can sometimes react to too much CO2 by becoming sluggish and hiding.

Just found a similar thread where it was recommended to place the diffusor next to the inlet, so that the bubbles would go straight into the filter and get dissolved.

Do bear in mind this will likely result in higher CO2 levels due to more efficient dissolution. If you are already overdosing CO2 then this has the potential to result in fish death - ensure that your CO2 levels are not too high before doing this. There is also some speculation that feeding CO2 into the filter inlet may have the potential to damage the filter impeller and/or rubber seals. I'm not sure if this is true, but it seems to be circulated online as a potential consequence quite often, so perhaps something to consider.

Once the co2 turns off, 1h before the light goes off, they are very active. Swimming around and having a good time.

Try doing a majority water change (like 60-70%) during the day when the CO2 is on, and see if they come out of hiding. This will flush out large amounts of CO2, and if the behaviour is a result of CO2 toxicity, they should come out and be active again.

 

[Nick potts]

I had a very similar issue with a group of around 20 embers, they would spend most of the day hiding and nip out only for food. I noticed as above that they became a lot more active at water change time when all flow pumps and CO2 were off, I don't know whether it was the calmer water (I ran a lot of flow through that tank) or the CO2 (no rapid breathing or other signs of distress).

I have since moved them into a blackwater tank with no CO2 and only sponge filters and they seem a lot more active.

 

[Tjoste]

Thanks for all the suggestions!
I did some more testing the last couple days:

Turned down Co2 and added good aeration over night. No change
Co2 completely off. No change
Turned off filtration and all flow for 30 mins. No change
Turned light down to 5%. Maybe a small change.

I usually have light on from 3pm to 11pm. At around 9-10pm they will start exploring the tank. I now see that this happens both with and without Co2.
This also happens whether I have strong light or just 5%, but they were really active last night with the lower lights.
What I tried today (still with only 5% light) was to turn the lights on at 10am. They were really active for a few hours, but I see now that as the normal light period is approaching (3pm), they are starting to hide again.
If they keep hiding all day and gets active again around 9pm, it must be some internal clock or something? As if I have set my light period to their natural rest/chill in the dark period 😂