Fish Pond Aerator

If you require a fish pond aerator over and above the normal filter and pump system you've installed, then you are likely carrying a high fish load.

Caution - Too High Fish Load

The caution about carrying too high a fish load and compensating with extra pond aeration to increase oxygen levels is that if you lose power, you'll lose a lot of your fish as the oxygen levels will quickly go below life support levels.

Creating Extra Oxygen

There are two basic methods of creating extra oxygen levels in the tank and both involve moving more water across the surface of the pond. This is where the critical oxygen/water interface happens and where oxygen is transferred to the water.

An Extra Pump

You can install extra pumps. In this case, direct the water flow either across the pond surface to move water laterally or direct it from the bottom straight upwards to move water from the bottom of the pond quickly to the top. In this way, you'll create a water movement cycle that will cycle water from the top to the bottom of the pond and equalize oxygen levels at all water depths.

The flow rate of these pumps will be determined by how many extra inches of fish you wish to carry over the natural carrying capacity of your pond. Remember the rule of thumb is one inch of fish for every square foot of pond surface

Fish Pond Aerator

The second method is to install a fish pond aerator, by putting the exit tube directly on the bottom of the pond, you'll create the same flow pattern as the pump example above to maintain oxygen levels. Note that most of the benefit from aerating ponds comes not from the bubbles themselves but from the increased water flow.

Note that both of these fish pond aerator systems do not add extra oxygen to the water, they simply help the water replace depleted levels faster.

And both can be used during the winter to help keep the ice clear in one spot of the pond to aid in oxygen exchange

Depending on the value of your fish, you might also consider a backup generator system that automatically comes on when your normal electricity system falters. Or simply be prepared to lose some fish.

Biological Processes

Having said that, understanding a few simple biological processes might make helping your fish survive your pond aeration efforts a little better.

Fish gills act much like our lungs do. They push water across the gill and absorb dissolved oxygen from that water, transferring the oxygen directly to the blood stream of the fish. (We take the O2 from the air through our lungs to the blood stream). If this O2 falls below a certain concentration (around 7ppm) then your fish has trouble breathing. A similar situation in humans would be when we go very high (like mountain climbing) and the O2 levels are reduced meaning both fish and humans have to work harder to get the oxygen we need to live in oxygen depleted environments.

Several things contribute to this in water environments. Hot water will make it tougher for fish to breathe. Poor aeration because of too low a volume of water being moved will do this. Accumulated ammonia levels from too many fish and not enough filtration/air movement will do the same thing. Imagine yourself in a room where someone is cleaning the oven with the door open. That's what it is like for a fish in bad water.

Aerator Could Be Critical

So having a good fish pond aerator system is critical for fish health. If you see your fish being lazy, lying around the bottom of the pond or gasping at the surface of the pond on a regular basis, then you know you have a problem. Increase the pond aeration or decrease the numbers of fish.

I note that parasites and other internal problems can make your fish appear to have O2 depletion. If increasing the size and/or quantity of your pond aerator system does not solve the problem, check for parasites.

Shopping Resources for this Article

Extra pumps in the pond

Fish pond aerator