Dropsy or Pregnant Guppy – How to Tell The Difference?

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Guppies are generally hardy fish, but they’re not infallible. They can sometimes struggle with a variety of health issues, like parasites, infections, and different diseases. All these come with numerous symptoms, many of which overlap.

Novice guppy keepers, especially, have difficulties differentiating between disease-related symptoms and normal behaviors and occurrences. Such is the case with pregnancy signs vs. dropsy symptoms, which can appear similar in many cases.

Today’s task is to help you differentiate between the 2. Without doing so, you won’t know whether your guppies need treatment or they’re simply pregnant, which will require a different approach.

Guppy Dropsy Symptoms

Dropsy is a somewhat rare condition in the guppy world. However, when it does occur, it can come with gruesome effects since the disease is also highly contagious. Some fish will have stronger natural immunity against it, but most will fall victim to its symptoms.

One of the most prevalent signs of Dropsy is the swollen belly, reminding of a pregnant guppy; hence, the confusion. Guppy females will develop an impressively bloated abdomen during pregnancy, making it difficult to tell whether the female is actually pregnant or experience some disease like Dropsy.

Fortunately (yes, I will put it like that for reasons I will explain later), Dropsy comes with several other symptoms, such as:

  • Overall lethargy and low levels of energy throughout the day
  • Lower appetite or refusal to eat at all
  • Erratic swimming patterns and swimming near the water’s surface
  • An unnatural, clearly visible curvature of the spine (bent spine syndrome)
  • Swollen and red anus
  • Pale and stringy feces
  • Bulging eyes and pale gills and, of course
  • A swollen and deformed belly

The reason why it’s a good thing that Dropsy comes with multiple symptoms is because it allows you to identify the condition faster. Confusing it with pregnancy will deprive the guppy from the treatment that could save its life.

Pregnant Guppy Fish

Guppy pregnancy is an opportunity for tremendous joy and excitement for so many guppy keepers. Until they realize that guppy females get pregnant every 30 days and deliver between 20 to 50 fry on average. Guppies are prolific breeders in the ideal environments and with enough diverse food available.

But how can you tell that your guppy female is pregnant, and what should you do?

There are several signs worth mentioning here:

  • Witnessing the mating process – Guppy males are extremely active creatures, especially during the mating phase. Guppies don’t have biologically predetermined mating seasons like other fish species. They will mate every month, with the whole process lasting for hours and multiple guppies participating in it. You should see the male swimming in front of the female, trying to impress her. At this point, the mating dance is in full display – a clear sign of the pregnancy to follow.
  • The inflated abdomen – Guppy females, are generally larger than the males with rounder and bigger bellies. The pregnancy will take things to the next level. The female’s belly will inflate to new peaks, often making their human keepers nervous. However, this is standard for guppy females, especially if this is not their first pregnancy and they will deliver more fry. No reason to worry; just prepare a new tank for when the female will go into labor if you want to keep the fry.
  • Watch for the pregnancy spot – The pregnancy or the gravid spot is nothing more than a darkened area towards the back of the female’s belly. The area will darken gradually as the belly grows, ending up completely black towards the end of the pregnancy. At this point, you will even distinguish tiny black dots in that area. These are the fry’s eyes watching and judging you. Jokes aside, those really are the black eyes of the offspring, now fully developed and ready for birth.
  • Visible behavioral changes – The first sign that something is different is the female’s seemingly unexplained aggression. The males will attempt to mate with the female even after she got pregnant. They will become particularly aggressive towards the guppy males, who tend to be very pushy during the mating phase. This can lead to constant harassment, stressing out the female and causing it to grow more aggressive. You should also see the female refusing food and seeking hiding places when the labor approaches.

These signs coming together tell the story of a pregnant guppy, so there’s no reason to panic. Just make sure you keep the female under close supervision. When the labor approaches, move it into a different tank to give birth. This will allow you to save the fry from the adults that could eat them upon birth.

Your fry will be big enough to care for themselves 3-4 weeks after birth.

Constipated Guppy Symptoms

Guppy constipation is more common in cases of overfeeding or when the fish don’t have enough fibers in their foods. It’s also a problem in fish who eat a lot of flake food and not enough live food and veggies.

The most compelling sign of constipation is the overtly inflated abdomen and lack of fish waste. If the fish’s digestive tract is blocked, the guppy won’t pass on any feces.

The guppy may also display buoyancy problems and unstable swimming. This is due to the inflated digestive tract putting pressure on the fish’s swim bladder.

Be careful, however, since erratic swimming and buoyancy problems are also indicators of other, more severe conditions.

Can You Treat Dropsy?

Late-stage Dropsy is usually deadly, which is why diagnosing the condition in its early forms is the key to a reliable treatment.

Here’s what you can do if your guppy shows signs of Dropsy:

  • Quarantine the sick guppy – This step is necessary to protect the rest of the guppy population. Depending on its causes, Dropsy can be highly contagious and deadly even in its primary forms. I suggest setting a new tank for your sick guppy, setting the parameters to the ideal values, and keeping the fish in the new habitat for a while.
  • Try to treat the condition – The treatment usually consists of several procedures. These include adding salt to the tank (1 teaspoon per gallon of water), using antibiotics, providing a fresh and balanced diet, and keeping the water clean. The recovery period will vary depending on the disorder’s severity and symptoms. The antibiotic treatment should deliver its most meaningful effects over the course of 10 days, for instance.
  • Consider euthanasia – If the treatment doesn’t deliver the expected results, euthanasia remains your only option. In advanced stages, Dropsy can bring down your entire guppy population fast. Killing one or several fish is only about choosing the lesser evil to save the bulk of your guppy population.

Is Dropsy Contagious?

Yes, it is contagious and can grow to deadly proportions fast. Dropsy is actually a bacterial infection caused by the Aeromonas bacteria. This bacteria thrives in poor water conditions resulting from inadequate tank maintenance, fish waste accumulation, decaying fish food, etc.

Fish with strong immune systems won’t have problems with short-term exposure to the bacteria. Their immune systems will only succumb to the microorganism’s persistency only due to prolonged exposure. But guppies with immuno-compromised systems will fall sick almost immediately.

The disease can then spread to other guppies with faulty immune systems, soon to infect the entire population. To avoid that, here are several preventive measures to consider:

  • Undergo regular water changes (change at least 25% of the water weekly)
  • Monitor water quality and water parameters like temperature, ammonia content, oxygenation, etc.
  • Avoid overfeeding (only feed your guppies once or twice per day and only what they can eat within a minute)
  • Remove fish waste and unconsumed food, preferably daily or every other day at most
  • Provide guppies with a varied diet, including live food, veggies, and various plants


If you’re unsure whether your guppy’s inflated belly is a sign of pregnancy or disease, quarantine the fish. This will allow you the space necessary to investigate the problem and consider the best solution available.

Read my other articles about guppy tank maintenance, diet, and breeding, and comment below if you still have questions.

Updated: November 16, 2021
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