Sunday, 14 July 2024


13 May 2021

This disease is caused by bacteria. These bacteria are present in basically every tank (including aquariums). They are not normally harmful to fish. However, we wonder why the disease occurs at all?


The reason is definitely a rapid decrease in the immunity of fish. It is caused by a poor diet. A bad diet means a diet without vitamins, too monotonous, too hard to digest, without microelements or one that causes intestinal blockage. Additionally, it is caused by rapid fluctuations of water parameters, poor water quality, the presence of chloramine or chlorine in the water, overcrowding of the tank, lack of sufficient dissolved oxygen, or inadequate stocking. These bacteria attack all the internal organs of the fish. This is the liver or the intestines. These bacteria cause them to shrink. And damaged kidneys cause accumulation of water in the body or unfiltered blood. The disease generally leads to an inflammatory response in the body. The progression of this disease can lead to the inevitable death of the fish.

Disease type

The disease is caused by bacteria.


The cause of septicaemia, or water dropsy, is the bacteria Pseudomonas punctata

Circumstances that favour the development of septicaemia

  • rapid changes in water parameters
  • incorrect nitrogen cycle, i.e. poor water quality
  • overfeeding of fish
  • weakened fish
  • Using a monotonous and unsuitable diet
  • the age of the fish - older fish are more prone to disease
  • Stress


  • protruding scales strictly in the abdominal area
  • bloated body - it is filled with body fluids also in the abdomen area
  • whitish and flat subcutaneous blisters causing numerous discolorations, i.e. ulcerated skin
  • frayed fins
  • blowing up of the eyeball
  • slimy, thread-like droppings
  • open gill lids
  • hiding
  • difficulty in swimming
  • swimming near the surface
  • bottoming out
  • apathy
  • lack of appetite

septicaemia in fish symptoms


This disease is very difficult to cure. Symptoms that confirm it are very advanced, and therefore internal organs are devastated. It is recommended to move the sick fish to a separate tank as soon as possible. Additionally, the root cause that caused the disease should be identified. You can try to cure the fish. However, the chance of this happening is very small. During the cure you should increase water aeration. You should rather not use intensive lighting. The temperature should be increased by about 2 to 3 degrees C.


  • TETRACYCLINE - 40 to 100 mg per litre of water. The bath is applied for five days. Repeat this action if necessary.
  • OKSYTETRACYKLINE - from 20 to 100 mg per liter of water. The bath is applied for a period of five days. We repeat this activity if necessary.
  • MINOCYCLINE - 250 mg per 40 litres of water. After a day, we change the water completely and apply the same dose. The drug must not be administered again.
  • AMPICYLINE and SYNTARPEN - administer 0.5 g of ampicillin and 0.25 g of syntarpen per 50 litres of water. Every two days the bath is repeated with a new solution.

All the above antibiotics are available only on prescription.

Baths in aquarium preparations:

ICHTIOMYCYN-C - dissolve one capsule per 50 litres of water. Before use, dissolve the capsule in 100 ml of warm water. After two days it is necessary to change 1/3 of the water. Then filter the water through activated carbon. If necessary, repeat the process.


When we detect the disease we have to find its direct cause. There is no evidence that the disease is contagious. Unless it is a secondary infection. After the appearance of a so-called exudate, the fish should be euthanized.


  • take care of good water quality - from time to time you should check the level of nitrite and ammonia, choloramine, chlorine, as well as dissolved oxygen in the water
  • do not cause sudden changes in the water parameters - including pH and temperature
  • use the right diet - it must be enriched with vitamins, varied and rich in microelements
  • do not overwater the tank
  • do not overfeed the fish - we give such an amount of food at one time that the fish are able to eat
  • we should limit stressful situations for our fish. When you change the water you shouldn't do it abruptly, choose the right fish stock, limit the use of chemicals and keep shoal fish only in larger groups.