Koi coming to surface frequently to gulp air

[smith]

150 gal pond with 4 koi 3-6"

Is this normal koi behavior or do they need more oxygen?

 

[j.w]

@smith
The pond is way too small for those koi, maybe not right now but in the future you better own a shovel for your new big huge pond
I would say that is not normal for them to be gulping air at the surface a lot. You might want to add an aerator for now to see if that helps.

 

[WaterGardener]

What are your water parameters? Nitrite can prevent fish from taking in oxygen. It can replace the oxygen in their red blood cells, so they suffocate.

 

[Mmathis]

Hello and welcome!

No, not normal. They probably need more oxygen as well as a much larger place to live. What kind of filtration do you have?