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Why Your Fish are Gasping for Breath at the Surface

HAVE YOU NOTICED YOUR FISH GASPING AT THE SURFACE?  It’s the warm weather causing havoc…

The onset of extremely warm weather has caused many pond-related problems – as it does every year.   Apart from the obvious algae blooms associated with high temperatures, the most prevalent issue is that of depletion of oxygen in your pools.  This causes a problem because balanced oxygen levels are vital for happy, healthy fish!  So, when your fish are gasping at the surface, this is because your pool oxygen levels are low…  Read on for an explanation of why – and how to combat this!


Peter, our in-house pond expert, explains that algae produce oxygen.  We spend our time removing the algae with ultra-violets and algae treatments which we do need to do to keep our pools nice and clear.  However, what people often don’t realise, is that destroying the algae removes oxygen from the pool.  This often can go unnoticed, until the hot weather produces problems…

In hot weather, fish need more oxgen because the high temperatures will increase the water temperature, reducing the oxgen available.  You might start to notice your fish near the surface of the pond on hot days, gasping for breath – this is when it becomes more noticable – and urgent.


There is a solution – but firstly, a common misconception is that fountains and waterfalls add enough oxygen to the pool to help.  Peter warns that whilst these things do agitate the surface of the water they do NOT oxygenate the bottom of the pool – meaning that the water is not oxgenated throughout.

Peter advises that one of the most important pieces of pond equipment (which is relatively inexpensive to buy and run) is an air pump.  An air pump forms a column of oxygen, coming from the base right through to the surface, therefore oxygenating the entire pond.


All fish will benefit from the oxygen an air pump supplies and, in some cases, it may save their lives in extreme weather conditions.  The largest fish always suffer first because they require more oxygen, so if you see any signs of them gasping, ACT IMMEDIATELY because this is the last symptom of oxygen deprivation.

Peter has recently experienced several emergency call outs to gasping fish; he has installed an air pump and within 24 hours the fish have recovered.  It’s such an important bit of kit!

Peter’s Top Tip: Remember, leave the air pump running 24 hours a day, 7 days a week – do not switch it off at night!

Remember, prevention is better than cure.

Happy Fish Keeping,



Peter Mills

Pond & Lake Management Ltd

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