Bubbler in Goldfish tank?

Hi guys! So I got my 55g with 3 fancy Goldfish (max stock for that tank). Everything is OK so far. Ammonia 0ppm Nitrite 0ppm Nitrate @10ppm (Pennywort works like a charm in their tank to lower nitrates :) PH 7.6 75%-80% water change weekly Fluval canister rated for 100g. Two HOBs rated for 20g, and a... show more Hi guys!

So I got my 55g with 3 fancy Goldfish (max stock for that tank). Everything is OK so far.

Ammonia 0ppm
Nitrite 0ppm
Nitrate @10ppm (Pennywort works like a charm in their tank to lower nitrates :)
PH 7.6
75%-80% water change weekly
Fluval canister rated for 100g. Two HOBs rated for 20g, and a Big sponge filter.

I notice though that one of my fish, goes up for air from the surface. She "gulps air". The reason I am worried is because this can lead to buoyancy issues.

Would adding a bubbler wall in the back add more "oxygen to the water" that way she won't gulp air from the surface? I have done some research online and some say it does not matter others say that it is not good to have those bubbler things for the fish. I have a big Sponge filter for biological reasons in the tank and that shoots bubbles to the top of the surface?

I guess my question is why does my fish gulp air from the surface while the other two don't? How can I help my fish get oxygen through the water column instead of her getting it from the surface?

Hopefully you can help me :)
Thank you in advance.
Update: Thanks for your input. I am glad that dude told you that one because obviously no fish belongs in a bowl not even Betta fish. My tank is 4 feet long dude. I have very good filtration and very good water chemistry. That is why I am asking why my fish still takes air from the surface. I can put a bubbler I guess, but... show more Thanks for your input. I am glad that dude told you that one because obviously no fish belongs in a bowl not even Betta fish. My tank is 4 feet long dude. I have very good filtration and very good water chemistry. That is why I am asking why my fish still takes air from the surface. I can put a bubbler I guess, but if that does not fix the issue then it's a waste of space in the tank.
Update 2: Patrick, then why is my Goldfish tanking in air from the surface? Zachary, I feed New Life Spectrum Sinking pellets for Fancy Goldfish. I also feed gel food that sinks to the bottom. The boiled veggies also sink. I do not give them floating foods. I live in Co. It's cold here. I have no heater on them just... show more Patrick, then why is my Goldfish tanking in air from the surface?

Zachary, I feed New Life Spectrum Sinking pellets for Fancy Goldfish. I also feed gel food that sinks to the bottom. The boiled veggies also sink. I do not give them floating foods.

I live in Co. It's cold here. I have no heater on them just room temp @68F. Their water is freaking cold. I hate doing water changes on them. lol
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