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Dead Fish? Most Likely It Is A Lack of Oxygen

posted Jul 28, 2011, 2:58 PM by Bob Whitney   [ updated Jul 28, 2011, 3:01 PM ]
    
Summer fish kills are not at all uncommon especially since more and more people want to stock tanks with a lot of fish and feed them often without doing the necessary fish removal, especially the big ones.
    This time of year we have several things happening all at the same time to cause a lack of oxygen in the water.  First, the extremely hot temperatures combined hot winds and no rain has evaporated a lot of water reducing water volumes significantly.  Less water means crowded fish and less oxygen.  Second a lot of algae and other plants begin to die off in this changing tank dynamic and this vegetation die off uses tremendous amounts of oxygen for decomposition.  Third, the fish in your tank have continued to grow all these years so that now you have more pounds of fish than ever and these bigger fish demand a lot more oxygen.  All of these factors combine together to cause a sudden fish kill because of a lack of oxygen.  
    What can you do?  First, monitor your tank frequently with the current weather situation.  Go out very early in the mornings and look for large fish coming to the surface gulping air.  This is when the oxygen levels are the lowest and the fish will tell you they are in trouble.  Second, if you haven’t fished your tank lately then have a fishing party highlighted with a fish fry.  Reducing numbers helps tremendously especially if you reduce the large fish.  Third, quit feeding fish in this hot, dry weather.  Fish feeds increase metabolic rates as well as provide something else to decompose.  Fourth, when all else fails provide oxygen with an aerator.  The best aerator is something that throws water up in the air like a paddle boat does.  Well water is the worst, it contains very little oxygen.  Fifth, call me so I know then the fish fry is!