Massive overnight die off in African Cichlid tank

[MaloK]

Colin T, I’m so glad you popped up now on this subject. The resident guru in another group is telling me I am at risk of providing too much oxygen to my tanks. He says this can cause a deadly incurable disease. He talked about bulging eyeballs and all kinds of stuff and I couldn’t read it, too traumatic after the death of my fish yesterday. His comment was in response to my conclusion that oxygen deprivation may have played a role in this die off. I told him I had ordered more of the large air stones I have other tanks & plan to use one at each end of the 125.

He said I may very well wind up killing the rest of the fish that survived. I plan on adding more fish to this tank when things settle down. I bought a colony of Burundi Frontosa and they are breeding up a storm. My intentions are to add one of those 2”x 4” air stone cylinders to each end. He says this could be a lethal mistake. What do you think?

Simply put, the oxygen level in water is controlled by 2 main factors, Temperature and Salinity. They both make-up what will be the saturation level. Once saturation level is attained there is no more gazes that will dissolve in the water. between 70F and 80F there is nearly a third less oxygen in the water already.

When Hypersaturation occur in nature, it's normally for a short period of time, but can be very high. It's not a problem for fish. In an aquarium you try to maintain it the lowest and constant. It's true that in the long term too strong hypersaturation is not good for the fishes.

Saturated water will have a tendency to create micro-bubbles swirling in the water layer. As long as these remain in low numbers and don't start to stick everywhere and overwhelm the tank. it's a visual token that the tank is adequately ventilated.