Reason Your Fish Tank Pump Not Working and Troubleshooting

Your fish tank pump can stop operating one day without warning. Inside the water, the pump causes bubbles to form. However, if it breaks down, the fish in the tank won’t get enough oxygen from the bubbles.

But what causes the fish tank pump to malfunction? How can the faulty fish tank pump be fixed?

Cleaning the pump, replacing the damaged motor shaft, repairing the power head wire, and replacing the rubber gasket are all necessary to address the problem of the fish tank pump not working.

If you want a detailed explanation of how to troubleshoot a fish tank pump that won’t turn on, keep reading.

What is The Reason for The Fish Tank Pump Not Working?

Pump failures in fish tanks are typically caused by dirty or blocked pumps. It is widely known that people who have problems with their fish tank pump maintain and clean their pumps improperly.

A damaged motor shaft, a ripped or broken power head wire, and a defective rubber gasket are some more causes. When the fish tank pump has been functioning for more than a year, these problems start to arise.

But when the motor inside the pump is damaged due to power surge, you may need to replace it.

4 Steps to Troubleshoot a Fish Tank Pump is Not Working: 

It is not advised to run a fish tank without an air pump. If the fish tank pump fails, the fish will suffer and eventually perish as a result of a lack of oxygen in the water.

Most individuals have a tendency to discard broken fish tank pumps as soon as they cease functioning. Nevertheless, based on the source of the issue, there are some clever solutions.

I’ll go over these issues in this article, along with solutions.

Things required to troubleshoot the fish tank pump not working:

Examine the equipment and supplies listed below for troubleshooting a fish tank pump:

BrushDistilled white vinegar (if needed)
SpongesMotor shaft (if needed)
Screw DriverA plastic tube (if needed)
TesterSilicone (if needed)
PliersEpoxy adhesive (if needed)
FilerBlow torch (if needed)

Step 1 – Clean the Cogged Pump:

First of all, turn off the power supply by turning the switch off. Now, unplug the water pump from the power outlet. Now pull the tube off of the power head.

Clean the Cogged Pump
Clean the Cogged Pump

Now pull out the water pump. Now, open the pump and pull on the notch to reveal the impeller.

open the pump
open the pump

Use a screwdriver to take the impeller out and clean the pump using brushes. Soak the pump inside hot water for 20 minutes. Now, you can use distilled white vinegar if the pump is clogged badly.

Step 2 – Changing the Broken Motor Shaft:

Take out the pump. And plug it in the outlet. Take out the broken shaft and turn it on. Now, insert a tester or screwdriver inside and see if it is magnetized.

Take out the broken shaft
Take out the broken shaft

If it is, the tester will be pulled to one side. You have to buy a new shaft. Now, cut it to the size of the previous one using a set of pliers. You might also need to file the edges. Afterwards, put it inside the impeller.

 put it inside the impeller.
put it inside the impeller.

Now, reassemble the parts and put the pump back together.

Step 3 – Repair the Power Head Wire:

First of all, cut the broken wire.

Repair the Power Head Wire
Repair the Power Head Wire

Now, cut the black wire and take out the black and red (in this image, blue and red) wires.

cut the black wire
cut the black wire

Now, insert two plastic tubes at two ends, one at the plug, and one at the pump end.

one at the pump end.
one at the pump end.

After that, heat the plastic tubes using fire from a blowtorch or a lighter.

Now, apply some heavy-duty epoxy adhesive on the wires and the tube and push the tube in.

After the epoxy adhesive has dried, apply silicone glue on top of the adhesive and tubes.

Now, do the same process for the plug. Wrap it with plastic tape, cover it with a plastic tube, and apply heat to secure it in place.

Step 4 – Replacing the Rubber Gasket:

After taking apart the pump, disassemble the air cylinder. Now, you can see the rubber gasket. Take it out using a screwdriver.

Take it out using a screwdriver.

Now, replace the rubber gasket with a new one.


  1. Always turn off the pump and pull out the plug from the outlet before doing any sort of troubleshooting.
  2. Be careful while cleaning the impeller. The small and thin blades can break if you put too much pressure on them.
  3. Make sure that the new shaft has the same radius matching with the previous one. Also, do not forget to file and make it smooth.
  4. Carefully handle using fire while heating the plastic tube. Use protective gloves.
  5. Keep some extra tubing if you need to change the place of the air pump while installing it.
  6. You should install a check valve if you want to stop leaking water.
  • Make a drip loop to prevent water from entering the power outlet.

Frequently Asked Questions: Fish Tank Pump Not Working

How to check the air pump to know if it’s working?

Detach the pipe from the pump and put your hand in front of the air outlet. If you do not feel any air flow, check for kinks. Get rid of the kinks. If it still does not work, inspect the inside for a broken shaft.

How to clean the mechanical filter of an air pump?

Use the water from your fish tank to rinse the filter of the air pump. Now, clean the dirty parts using brushes. After that, use tap water to clean away all of the dirt from the sponge. You may need to replace the sponge if it is too dirty.

How to get rid of noise coming from the fish tank pump?

Always keep the inside of the fish tank clean. Get rid of food waste and fish waste. Always try to keep the pump on top of the water level. Also, put the pump on top of a hard surface.
Changing the diaphragm may also reduce the noise coming from the air pump.

Can a fish stay alive if my fish tank stops working?

Without insufficient or no oxygen supply the fish won’t be able to survive for more than two days. The oxygen will reduce gradually.
If you notice that the fish are at the top of the water level and gulping for air, it is an indication of a failed fish tank pump. Also, if the fish move their gills fast or keep resting for a longer period, they might die of low oxygen levels.

How many types of the fish tank are available in the market?

There are mainly 6 types of fish tank pumps available. These are air pumps, submersible pumps, wave-making pumps, internal water pumps, external water pumps, and dosing pumps.

Final Verdict

You may have problems with your fish tank pump suddenly or while out of the home. However, it is usually due to unclean insides or fractured shafts. You can simply repair it if you clean it carefully and replace the broken shaft.

Your fish may suffer if you do not repair a broken pump. It may be difficult to detect a faulty pump. Check the pump for indications of deterioration or faults regularly.

I’ve provided a troubleshooting approach for resolving the problem when the fish tank pump stops operating. To achieve the best results, carefully follow the instructions.

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Arif H Fahim

Welcome to PetFishTank! My name is Arif. I make an effort to publish educational articles using my many years of expertise as a fish owner.

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