too much oxygen?

[Phoenixphire55]

I have a new 30 gallon tank with a canister filter, bubbling fish statue, bubble curtain, and soon I'm putting a small powerhead in near the surface. I have 5 goldfish of varying smallish sizes in there temporarily until I move. My question is whether its possible to have too much oxygen in the water? What are possible problems that could arise from overly oxygenated water? Mold?

[black hills tj]

I don't think you have anything to worry about. You will just have high oxygen content and high surface agitation which means more gas exchange.

[tawolcott]

I got a canister, powerhead, 2 bubble wands and an airstone. The only problems I have are my electricity bill. Point the powerhead toward the front glass and you'll never see algae on it again. The only place I get glass algae is the back so I am considering either getting another small PH to point back there or redirect the canister flow to it. Flow against the glass rules the day.

Not to mention, my fish seem to enjoy 'rising the wave' along the front glass.

[fearlessfisch]

I have seen occasional comments online suggesting that oversaturation of oxygen and excessive air bubbles in the tank can be associated with popeye in fish. I am skeptical, though, that this would be a frequent occurrence. I think the most frequent cause of popeye is poor water conditions. I certainly would feel much safer having excessive oxygen and clean water than having dirty, low-oxygenated water.

Sometimes it is hard to tell what is myth in the online world. I honestly don't know if oxygen can cause or aggravate popeye in fish. Perhaps someone more knowledgeable could chime in and comment on this.

[black hills tj]

I've never heard of the popeye theory.

[neilanh]

I don't think it's possible to overoxygenate the water like that. When the bubbles from the statue or bubble wand break the surface, what happens is it causes the oxygen levels in the tank to balance with the atmospheric oxygen level. The bubbles in the water actually very little, almost nothing, towards upping the O2 level, it's moreso the breaking of the water surface that mixes the gases in the tank with the gases in the air around you.

Heavily planted tanks are a different story, in that you can actually saturate the water with O2. When you hear of people talking about plants pearling, that's what's happened.

[Purrbox]

In heavily planted aquariums it's possible for the plants to saturate the water with oxygen to the point where it can't absorb anymore oxygen and the rest is released as bubbles (called pearling at Neilan mentioned). Generally fish in these aquariums are the healthiest that you'll find. So no, too much oxygen is not a problem.