Gas bubble fish disease

Gas bubble disease

1. General description

The primary source of oxygen in water is atmospheric air – oxygen (and other gases in the air) penetrates into the surface layers of water until the appropriate degree of saturation (to equilibrate). The amount of gas which dissolves in liquid is proportional to pressure this gas (in definite temperature). Pressure change causes that the amount of gas in atmosphere and amount of gas in liquid strive to balance all the time. Reducing or increasing the atmospheric pressure causes that degree of saturation of water with gases also changes until both pressures will be aligned. This change is gradual and pressure difference between the two environments is slight. Then this occurrence doesn't cause any negative effects for fish.

Second source of oxygen in water is process of photosynthesis. The amount of released oxygen by plants is proportional to their ability to conversion of carbon dioxide and water into other compounds. Favorable conditions (strong lighting with red spectrum or high insolation) and additional green organisms (mosses, algae) increase the rate of photosynthesis. Then the water may be supersaturated by oxygen and its pressure may significantly increase. At this point excess of the pressure will be released into the atmosphere and gas comes out of the water in the form of bubbles because pressure difference between the environments water-air is large and reduction is rapid.

Then pressure reduction occurs also in fish bloodstream – pressures strive for balance between water in its gills and its blood (blood pressure is higher than water pressure in gills). This occurrence is rapid so released gases, mainly nitrogen, cause bubbles. These bubbles block blood vessels and they gather in tissue and body fluids. Then we have to deal with gas bubble disease but described cause of water pressure change in aquarium is only one of the possible causes.

2. Type of the disease

This disease is caused by environmental factors.

3. Cause of the disease

Cause of this disease is rapid change in fish blood pressure.

4. Favorable circumstances for development of the disease

• lot of green organisms (plants, mosses, algae) and propitious conditions for intensive photosynthesis their organisms at the same time,
• excessive consumption of oxygen by decomposing organic matter and an aquarium with plants without additional source of oxygen and without enough light at the same time (in the case when the tank had previously strong light),
• rapid increasing water temperature (with increasing water temperature decreases degree of water saturation gases and decreases pressure these gases),
• usage of tap water for fill of the aquarium and this water wasn't left to equalization of pressures between air and tap water,
• bad use a pump (inadequate a pump for size of the aquarium, number of plants and fish).

5. Common symptoms of the disease

• timidity, hiding,
• sluggish movements,
• loss of appetite,
• swimming under water surface
• swollen eyes,
• fast movements gill covers,
• apathy,
• excessive secretion of mucus, blisters on the skin,
• swelling of the body,
• loss of balance

6. Types of the treatment

First we must eliminate factor which causes this disease, fish we must transfer to a separate aquarium with properly prepared water (we should leave this water for several hours to remove unwanted components) and oxygen-rich water (oxygen concentration in the water should be 14,6mg/l). The general tank we leave to equalize pressure between the atmospheric air and saturated gases in the water. All symptoms of the disease should retreat after a few days unless the changes in the body are too advanced (e.g. gills have been damaged). Then we should commit an act of euthanasia these fish. Healthy fish we transfer back to the general aquarium and we should use adequate vitamin preparations and water treatment conditioners in order to strengthen their immune system (e.g. Tetra AquaSafe, Sera Aquatan, JBL Atvitol, etc.).

7. Comments about this disease

• Gas bubble disease occurs only when there is too fast pressure equalization between fish blood (high pressure) and environment (low pressure). This disease is similar to human decompression sickness.

8. Prevention

• we should avoid rapid changes in water temperature, lighting and oxygen concentration in water,
• we should properly acclimate new fish – we should gradually equalize the pressure between water in bag and atmospheric air,
• we must only use correctly prepared water for aquarium fill or partial water changes – we never use tap water for this,
• we should use optimum number of plants, we should avoid algae plague and we should systematic clean our aquarium from decomposing organic matter.