# Oxygen problem?



## SeaNote (Jul 18, 2009)

Here is what happened - not sure what is relevant or which came first, but...

Had a heater malfunction and temperature rose to 88 degrees. Had an algae bloom. The 6 Ottos I have had for over a year died within 12 hours. All other fish in the tank survived (mostly Platys / swimmy fish, but the Ottos were the only algae eaters/bottom feeders).

I immediately tested the parameters and they could not be any more perfect. A water change and a few days without lights cured the algae bloom.

It has been suggested to me that the Ottos may have died due to lack of oxygen because the algae bloom. So, I assumed it was okay to re-introduce some algae eaters. They died pretty quickly and all of the Platys hover at the top of the tank like there is not enough oxygen.

I have a 60 gallon with two filters and have had the same setup for over two years. I have just reduced the amount of water in the tank in order to get more surface agitation.

I am looking for ANY help / ideas.

Thanks!


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## James0816 (Jun 19, 2009)

Unless you see them at the top gasping for air, I would not suspect a lack of oxygen. Oto's are very sensitive and the high temp would definately do them in. They can be hard to establish in a tank due to the sensitivity as well. A very slow acclimation process usually does the trick.

Running the two filters should give you plenty of aggitation.

One thing that comes to mind immediately when you mention the high temp is ammonia. It will accelerate under those conditions. However, you mentioned that the water tests were good. Can you post your parms and how often do you do you water changes?


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## Dmaaaaax (Nov 20, 2008)

Higher water temperatures = less oxygen. In the winter time this can be a silent killer of fish if you do a large water change. Why? Well in the winter your water is colder, so you probably use warmer water from your tap to get it close to your tank's temp. You essentially are using more warm water from the water heater along with the colder water from the ground. The warm water from the heater (> 100F) is completely void of oxygen.

I learned my lesson last year and only use cold water, that I heat and aerate overnight in a 20g trashcan before doing my water change the next day. Not sure if this is your problem, since you mentioned doing a water change, but just something to consider.


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