Lack of oxygen emergency

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Apr 22, 2019
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Frampton Cotterell
I have kept fish now for 35 years, and have a stable mature 180L Juwel community tank. I cannot remember the last time any of my fish were sick, which is probably due to weekly maintenance including 35% water changes, and not overfeeding. I only feed 3 times a week. Most of my fish are 8/10 years old.

The purpose of this post is to warn other members of the importance of ensuring a good oxygen supply to the tank. In my tank the outflow pipe from tne Juwel pump is pointed up towards the surface of the water, so that it makes a ripple on the water surface to help oxygenate the water.

I had an emergency today. I had been away from home for probably 18 hours, and when i got back I noticed that the outflow pipe from the pump was on the floor of the aquarium. I can only imagine it may have been knocked off my one of my larger fish. More importantly my two beautiful 8 year old male Boesemani Rainbowfish lay dead on the aquarium floor.

I can only assume that with the pipe knocked off there was no ripple on the water surface, and the tank would slowly become depleted of oxygen. Boesemani Rainbowfish are particularly susceptible to low oxygen, and obviously did not survive. Other fish like Yellow Gourami's and Albino Corydoras can take in air by breathing air through their mouths at the water surface, and therefore were more able to survive. You might notice these fish suddenly dart up to the water surface for air.

Although my emergency came about through some sort of accident it just goes to show how quickly a tank can become depleted of oxygen, and the affect it can have on certain types of fish.
Sorry for your loss, thanks for sharing. I hope to achieve such longevity with my fish as I progress on the hobby.
That’s a really good thing to know and something that is not just overlooked but , many times , not even thought about . I am very impressed by the longevity of your fish and your feeding schedule . Very interesting .
I have the output for my built in sponge filter aimed at the surface for agitation but also rely on the air stones for my under gravel filtration. Air stones don't add nearly as much oxygen as one may think but they do cause a lot of surface movement.
Air stones add O by the bubbles breaking the surface. They also create some flow. But for the bubble to inpart any O into the water we would need our tanks to be at least 3 feet deep or more. It takes a long contact time for an air bubble to put O into the water.
Air stones add O by the bubbles breaking the surface. They also create some flow. But for the bubble to inpart any O into the water we would need our tanks to be at least 3 feet deep or more. It takes a long contact time for an air bubble to put O into the water.
Agreed but they add a lot of surface agitation.
While this is true for most fish I think it's worth mentioning there are exceptions to the rule like our anabantoid friends. They prefer low surface aggitation and breath air from the surface as well. When I was new to keeping fish I didn't know that about a betta I bought because it was in a large well stocked tank along with a lot of other fish and the flow was moderate on it. Putting these types of fish in a high flow tank is not good for them and they usually die early because of it from my experience.

I have a slow drip going on the current betta tank I have. There's also red cherry shrimp in the tank.

My rope fish is a lung fish from low oxygenated waters... mostly... and does a fair amount of surface breathing. I can see what you mean about surface agitation possibly be an issue if there is too much. The way I have mine setup is that the outlet for my right side built in sponge points mostly straight forward but just a bit to the right toward the glass. The two air risers for my under gravel are center and left side. The center is pointed pretty close to straight forward but the left is pointed more to the right. This results in the left third, or there about, having very little surface agitation.
That is surely very hard to digest. I mean... Outch Outch OOutch !!! That is the most unfortunate thing that could have happened.. I nearly broke my glasses facepalming myself wen I read your post.

I always used the smallest air stone to a minimum, just enough popping to prevent the biofilm accumulating on top, keeping a clear surface. In addition to the filter agitation. and it always was enough.

I also never personally had very delicate fishes.

If you have the means, a rain bar gives incredible gas exchanges. and prevent any biofilm to build, They have to be used with caution. and are beloved by rainy forest slow water movement fishes. And any fishes in my opinion.

When you're dripping. They make a lots of music. The plants loved it and invaded the place even with ridiculous light.

The tank looked ugly There were too many fishes in there... I was a noob, But they lived too long.

Imho, You where getting close to Guinness records, Every time I passed a fish beyond his life expectancy in the few tanks I possessed, I cracked a bottle of champagne.

You probably singlehandedly proven that I overfeed "naturally" and that an adequate diet in right proportions makes all the difference.

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