[Stoke88]

One of my 5 Angelfish has been coming to the top for air and I don't really know why. Its the only fish out of my 15 Cardinals, 6 Sterbais and 4 other Angels doing this. I just noticed this while doing some maintenance. I quick threw an air stone in there to see if that helps. Its a heavily planted low tech 75g aquarium so shouldn't oxygen be prevalent? My Fluval 406 spray bar is below water level creating no bubbles at all. Could this be the problem? That was the only thing I can thing of but if the water level is at or below the spray bar it seems like it creates to much of a current in the tank. Any help is appreciated.

 

[SeaHorse]

Hi Stoke88.

Prior to the air stone going in, did anything in the tank break the surface of the water? Usually the return from the filter is placed in such a way to break it. Yes this is required or the tank has the effect of being stagnant. Yes this will cause a fish to seek air at the surface.
Whether the spray bar is above or below, the same force is coming from the filter. The fish are still feeling the water flow. If you put the spray bar across one end you can actually create a river effect down the tank. Mine face "up river" most evenings. lol

Raise that spray bar and see what effect it has on them. Doesn't have to be above, but must break the surface.
Keep us posted on any changes.

 

[Stoke88]

There wasn't anything breaking the surface until I added the air stone. So more than likely this is the problem?

 

[MoneyMitch]

i agree with jackie here, therte has to be some surface movement or your going to get the stagnet situation. yes the plants put off oxygen but you still need some exchange at the surface, fresh air in and out but not so much to where you are gassing off all you co2 from the fish. its a thin line to walk and even harder balance to achive.

 

[Stoke88]

I left the airline in all night and day and everyone seems to be okay. The one Angelfish who was air breathing has stopped. Could I leave the air stone in for a while without hurting my plants?

 

[SeaHorse]

I can't answer that one for you. There are 2 diff processes in photosynthesis so I wonder if it would be ok at night. Hoping MoneyMitch can answer that one for us both.

 

[MoneyMitch]

I left the airline in all night and day and everyone seems to be okay. The one Angelfish who was air breathing has stopped. Could I leave the air stone in for a while without hurting my plants?

if your seeing a improvement in your fish you will be fine, however at night (lights off) plants revert from produceing oxygen and switch to co2 if memory serves me right. over the short term you will be fine with the air stone 24/7. but in the long run this will gass off the co2 in the tank and your live plants will come to a crawl if not stop growing all together without co2 and you will see a algae outbreak. its easy to treat the problem but to prevent that is where our challenge comes in.

i would reccomend adding surface movement during the day via a hob filter or even a powerhead close to the surface but not a air stone. maybe putting the airstone on a timer with your lights so that it kicks on when lights go off will help with the overnight co2 buildup and keep the fish from gasping.

 

[SeaHorse]

Of course raising the spray bar up to the surface works too. Thanks MM.

 

[pop]

Hello:
I thought that oxygen diffused across the surface tension and that breaking the surface tension increased the surface area thus increasing the rate of oxygen diffusion.
You can also increase oxygen diffusion into the water column by lowering the water temperature and by increasing the air flow across the surface of the water column removing excessive carbon dioxide from the atmosphere in contact with water.

Diffused oxygen is stratified in the water column and can be thought of as a gradient with the greatest dissolved oxygen saturation where the water column is in contact with the atmosphere and the greatest carbon dioxide saturation at the bottom of the water column where the plants are.

Floating plants might have a negative effect on oxygen diffusion by reducing the surface area of the water column and by the production of carbon dioxide through respiration.


One might think that air bubbles increase the surface area of the water column because surface area is defined as the point where atmosphere is in contact with water.


Note: this post is based on speculation only and there is no reason to consider the reasoning as being factual.

pop

 

[MoneyMitch]

Note: this post is based on speculation only and there is no reason to consider the reasoning as being factual.

pop

enough said

 

[pop]

Hello MoneyMitch:
I enjoyed your post …enough said ….. (I take it you know a reason for my considerations to be factual?)…. It gives one a good belly laugh.

It’s been fun.
pop

 

[Byron]

Getting back to the original issue, Stoke88, I would take a very different approach. In my opinion, this has nothing to do with oxygen in the tank, or you would see all fish gasping at the surface. One fish doing this when the other fish are behaving normal [I assume from your data they are] is clearly a specific health issue with the one fish.

I have seen this, in a tank of 130+ fish, where one tetra will remain hanging at the surface. Sometimes it recovers, more often it dies within a few days. I've no idea what might cause this. I have one pencilfish in my 90g behaving like this as we speak; it is also off-colour, a bit washed out. Is or was the angelfish showing normal colouration, with clearly-defined patterning?

Increasing water movement, aeration, or the plain old water change will often help the lone fish. But from this we cannot jump to the (erroneous) conclusion that there is some sort of oxygen deficiency in the tank. This is very highly unlikely in any aquarium with sufficient and working filtration.

Keep an eye on the fish doing this and let us know what follows.

Byron.