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11.4. Dropsy

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Author : David Bogert

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Time To Read :
4 minutes
Difficulty : Level 6

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Dropsy and bloat are two conditions seen often in fish. Both mean a fish which is swollen up. The terms are sometimes used interchangeably and sometimes they have different meanings.

Dropsy and bloat are two conditions seen often in fish. Both mean a fish which is swollen up. The terms are sometimes used interchangeably and sometimes they have different meanings. This article will use the following differential:

Typically Non-cichlidsTypically Cichlids
Caused by swelling internal organsCaused by intestinal obstruction
Higher up on fishLower down on fish
Almost always fatalCan be cured
Dropsy versus Bloat in Fish

It is important to differentiate between dropsy and bloat. If the fish has bloat go to this link:

11.3. Malawi Bloat

This article is only on dropsy.

Betta with dropsy
Betta with dropsy


In dropsy the abdominal cavity becomes swollen because an organ or organs inside of it becomes swollen. Common causes include:

  • The tube draining the kidney becomes blocked by an infection and the liquid wastes from the fish back up, swelling the kidney like a grape.
  • The liver, gall bladder and/or spleen become infected and swollen with yellow white fatty bodies called granulomas.

The infectious agents which cause these two types of infections number in the hundreds, so treatment is problematic. In any case by the time the fish swells the organ in question is failing and the fish will almost always die.

Dropsy is largely a disease of fish which are not cichlids. It is especially prevalent in inbred balloon platies, bettas and fancy goldfish, indicating a genetic component. Note that sometimes some breeds of fancy goldfish get what appears to be dropsy, but it is just the way they are built. They live for many years like that.

In advanced cases of dropsy, the fish’s scales stick out from the body in a “pine cone” effect.

pine coning in fish
pine coning in fish

When presented with pine cone dropsy one can try to treat by adding a broad spectrum antibiotic to the food in the hospital aquarium. But fish with pine cone dropsy typically die. Most fish with “pine cone” scales sticking out from a severely bloated body should simply be euthanized.

Treating Dropsy

If you are stubborn and have a case of dropsy in a valuable fish, treat for bacterial disease. Most aquarium bacterial diseases are gram negative infections and are best hit with a broad-spectrum antibiotic effective against gram negative bacteria. These need to be obtained from the internet.

They include Midland Vet Service Aqua-Mox, VetDepot Amoxicillin, Fishbiotic Ampicillin, Mardel Maracyn 2, SeaChem KanaPlex.  These medications are only available over the internet. Fish stores have all gone over to “natural” medications which have a very high profit margin and simply don’t work.

Dropsy and Pineconing
Dropsy and Pineconing

Bacterial infections are most effectively treated with antibiotics in the food. Many believe (and the instructions on the antibiotics say!) that antibiotics need to be added to the water. They are simply incorrect. This controversial topic is covered in the following link:

12.5. Fish Don’t Drink

It is easy to make medicated food. Heat 1/4 cup water (two ounces or 58 milliliters, not a lot) in the microwave. Then blend one 1/4 ounce of plain animal derived gelatin (Knox gelatin, one envelope) into the hot water with vigorous stirring. Take two tablespoons of dry commercial fish food (pellets or flake) and mix it with just a little of the hot water/ gelatin mixture. Add hot water/gelatin until you get a paste like consistency. If it gets too watery just add more food.

Then add roughly 1/16 teaspoon (a 1% to 2% addition) of the medication to the mud. Mix and mash the whole mass thoroughly.  Spread it out into a pancake about 1/8th inch (3 mm) thick on a plastic film or a plate. Then put in the refrigerator. If you plan on keeping it for more than two weeks put it in a small plastic bag and freeze.

Feed this to the fish. These antibiotics are FDA approved for use in humans so they are extremely safe. They are so safe they can be overdosed with relative abandon. They are non-toxic in over doses if only used for less than two weeks.

Dropsy in a fish
Dropsy in a fish

Dropsy has hundreds of possible causes so treating for bacteria will only cover the most likely culprits. Sometimes even the best laboratories cannot come up with a “cause” for dropsy.

One YouTube video maker had a lot of fancy butterfly goldfish. She knows her stuff and kept them in very good conditions. All her fancy goldfish died of infectious dropsy in a few months. She had the fish analyzed by the University of Florida (simply the best fish pathology department there is) and they were able to say it wasn’t bacterial and it was an infectious pathogen of some sort that attacked the kidneys. They couldn’t identify the pathogen. That’s a tough thing to have happen, but it shows even the best of the best often can’t come up with answers when fish die.

The symptom of dropsy is often accompanied by another symptom. These symptoms are covered separately in these articles:

11.2. White Poop

11.5. Sunken Belly

11.15. Fish not eating