How do fish die?

Human causes leading to fish deaths
Do you know how fish die? There are many human causes that lead to the death of fish, and we list the most important ones below:

Agricultural waste and fertilizers

The entry of agricultural fertilizers into surface waters, such as lakes and streams, stimulates the growth of microorganisms that consume the dissolved oxygen content in the water, leading to the suffocation of fish and aquatic organisms due to the deterioration of water quality, and also causes unpleasant odors.

Dumping nitrogen and phosphorus-containing waste into water bodies, such as heavy metals and pesticides, kills fish; as these wastes accumulate in the water, they decompose over time and break down the materials, thereby reducing the oxygen level in the water.
These wastes also promote the growth of algae that fish feed on, but these algae harm them as toxins accumulate inside the fish bodies. The presence of algae in the water affects water quality and blocks sunlight.

Sewage water

The pollution of seawater by the entry of sewage into it leads to the spread of certain types of bacteria found in humans, such as Escherichia coli, which causes disease. The solids in wastewater also affect the purity and color of the water, making it murky and dull, which impacts the fish’s ability to see around them and their ability to breathe.

Sewage contains microorganisms, and when it is discharged into rivers or seas, these microorganisms decompose and use the dissolved oxygen in the water for aerobic respiration, reducing the amount of dissolved oxygen in the water, and thus fish will not be able to survive.

Chemical leakage

Fish lay their eggs in shallow water areas or in waterways. Chemical spills such as light crude oil and petroleum products like diesel, gasoline, and jet fuel kill the eggs in these shallow waters. Light oils and petroleum products are highly toxic to fish, especially during the spawning stage.

Natural causes that lead to fish deaths
There are many natural causes that lead to fish deaths, and we list the most important ones below:

Oxygen deficiency

Oxygen deficiency leads to the death of large quantities of fish, especially in the early dawn hours. Symptoms of oxygen deficiency appear, such as the abnormal distribution of fish, where they spread to the edges or entrance of the pond.

Lack of food

A lack of food causes fish to feel hungry, and if it continues, it may lead to their death. Fish can live for 3 to 7 days without food, and some species can last for two weeks, thanks to their body mass. And having a sufficient amount of fat.

Aging

Aging is one of the natural causes that lead to the death of fish, and some signs indicate that fish have reached old age, such as weight loss, eating less food, swelling around the eyes, changes in body color, fish floating on their side, and eventually showing breathing problems.

Disease

Fish are sometimes exposed to parasites such as tapeworms, roundworms, or leeches, or they may be exposed to viruses or bacteria that cause fish deaths, which usually occur in fish farm ponds, leading to the death of large numbers of fish.

Usually, some symptoms indicating fish disease appear, such as loss of appetite, lethargy, reduced activity, or unusual behavior, in addition to visible ulcers, bleeding, or small black or white spots, among others. In this case, it should be treated in specialized tanks. Under supervision and control.

Reasons for the death of ornamental fish in the aquarium
There are several reasons that lead to the death of ornamental fish in the tank, and among the most important are:

Stress and pressure

Stress and tension are among the most common causes of death in ornamental fish, and there are several reasons that lead to stress, including the small and crowded size of the tank, the presence of a large fish that makes them feel uncomfortable, or the fish swimming continuously up and down, making them appear stuck in the tank.

The size of the fish tank is not suitable.

The aquarium should be chosen in a size appropriate for the place where it will be placed, and accordingly, the fish that will live inside it can be selected. However, if fish of inappropriate sizes are placed in the aquarium, it leads to their death. Death.
The incompatibility of fish species within the tank with each other
Some types of fish are aggressive and chase other fish, so they should be combined with types of fish that can defend themselves, for example.

Water specifications are not suitable

Water with healthy characteristics must be provided to maintain the life of ornamental fish, and to avoid early death of the fish, strips must be provided to check for nitrates, ammonia, pH levels, and more.

Overfeeding fish

Only one meal should be provided per day, and the fish will consume it within a few minutes. It is important to look for good quality, use several types, and alternate between them.
Not cleaning the ornamental fish tanks regularly
The aquarium should be cleaned monthly, and it takes 30 to 60 minutes to clean it.

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