Why Is Your Guppy Swimming Upside Down? (SBD Explained)

There is good news if you see your fish swimming upside down. It is not an immediate death pronouncement and there may be time to treat the problem. 

Perhaps one of the worst moments of a fish owner’s day is walking up to the tank to see one of your aquatic friends struggling to right themselves in the water. In our minds, swimming upside down is preparatory to floating upside down and not swimming.

Let’s take a look at some signs to observe and a step-by-step list of actions you can take so you can continue to enjoy your guppy. The most likely reason for your fish swimming upside down is a common ailment called “swim bladder disease.”

If this fish is part of teaching your kids to be responsible with pets, bring them along. They will benefit massively from learning how to keep their heads clear and the treatment ready.

Signs To Observe

First of all, swim bladder disease is fairly common among fish. Most of the reasons that it occurs have to do with trauma to the fish, either internally or externally. It can also be congenital, meaning they were born with the condition.

Unless you hatched the fish yourself, you will not be able to know whether it was congenital or trauma-based until treatment either works or fails. The best starting procedure, during observation then, is to isolate your fish in an isolation tank.

If you do not have an isolation tank, then isolate them in a small fish net to keep them from breeding with the other fish. Observe for the following:

  • Fins clenched. Most fins will spread to give maximum drive. The lethargy associated with swim bladder disease will cause the fish to conserve energy, including the energy required to spread the tail fin.
  • Distended belly. Often times swim bladder disease will include other organ function but can be caused by digestive problems. Observe the belly of your guppy, which is normally translucent. If it is distended, it will be easier to see through and observe bloating and stored food waste.
  • Erratic swimming. The swim bladder helps your fish in staying in one place with minimal effort. It allows fish to surface and dive at will. When compressed by other issues, it will be lopsided, much like having inner ear problems will cause you to stumble. They may swim sideways, upside down, or even rapidly without seeming to gain any movement.
  • Lethargy. Your guppy may, to conserve energy, stop fighting the current and simply lay at the bottom of the tank or float to the surface.


Much like the logical magic of Occam’s razor, made famous in television and movies, it is good to start with the simplest issue and least traumatic treatment.

1)         Check the tank temperature. According to Dr. Jessie Sanders only ten percent of cases diagnosed at home as “fish bladder disease” are actually fish bladder disease-related. The first culprit is the temperature of your tank. If it is wildly off, allow the temperature to slowly rise to normal and the issue should fix itself.

2)         Change their diet. If the belly is distended, either external shock from bullying or constipation from low-quality food has caused your guppy to stop passing waste, then isolate them and feed them three or four boiled and peeled peas a day until the problem resolves.

3)         If the diet and temperature have not fixed anything, use an Epsom salt float. Epsom salts have the same effect on guppies as on humans, in relaxing muscles. Often times it will help to ease traumatized organs that have invaded the bladder space and can help constipation problems. These are the steps for the Epsom salt bath.

  • Fill one bucket with one gallon of water that is the same temperature as the tank.
  • Dechlorinate the water.
  • Add one tablespoon of Epsom salt.
  • Add your guppy for fiteen minutes.
  • In a second bucket dechlorinate a gallon of water and add a teaspoon of salts.
  • Allow your guppy fifteen minutes in that treatment.
  • Return them to the tank.

4)         If the prior three steps have not worked, it is likely a bacterial infection and actual swim bladder disease. Consult your veterinarian for their recommendations on products. The best commercially available products are API Melafix for bacteria. If you suspect it may be a parasite related then BettaMax is a better alternative.

betta care facebook group

Don’t Give Up and Keep Watching

We don’t build aquariums to add more stress to our lives. That’s what jobs, PTA meetings, and traffic are for. We build these aquatic wonderlands to enjoy the serenity of our fish swimming in the bubbly worlds they occupy.

If your guppy is swimming upside down, there is a 90% chance that you can treat the problem without even leaving your home. In the event it’s an actual sickness, it is still highly treatable.

One final warning from Dr. Sanders is to avoid the popular fish floaties method, whereby fish owners give what amounts to floaties to their fish. These do more harm than good. Be patient and follow the process.