Why do fish have fishy smell? Why do freshwater fish have fishy smell?

All fish have a fishy smell, but the fishy smell of freshwater fish and sea fish is different. The fishy smell of freshwater fish is due to humus in the living environment, so actinomycetes will enter the blood through the gills, resulting in fishy smell. The fishy smell of marine fish is due to its own trimethylamine oxide, after the death of fish, this substance will be decomposed by microorganisms into trimethylamine, so it will emit fishy smell.

First, why is there a fishy smell

All fish have a fishy smell, but the fishy smell of freshwater fish is not the same as that of sea fish. Marine fish live in seawater, their osmotic pressure is lower than seawater, so water will continue to lose, in order to prevent water loss too fast, so need some amino acids and amines to fill the cells, which contains trimethylamine oxide. The substance itself has no taste, but when decomposed by microorganisms, it turns into trimethylamine, which emits a fishy smell. The fishy smell of freshwater fish mainly comes from the environment, because they live in ponds, lakes and rivers containing humus, which contains a large number of microorganisms, including actinomycetes can enter their blood through the gills, resulting in its earthy smell.

2. How to remove the fishy smell from the fish tank

1. Bacillus: Bacillus is a kind of bacteria, which is widely distributed and exists in soil, water, air and animal intestines. This bacteria can effectively decompose hydrogen sulfide in water, thereby reducing the fishy smell of fish tanks.

2. Light and bacteria: There are many kinds of light and bacteria, which are widely used in aquaculture. They can effectively degrade toxic substances such as nitrite and sulfide, and therefore are of great help in removing fishy smell.

3. Activated carbon: Activated carbon has the function of adsorption, so it can remove the fishy smell. Generally, it should be placed at the water inlet or outlet of the filter bin of the fish tank. It should be noted that this kind of thing has a life span and will be replaced after saturation.

4. Cleaning the filter bin: Another way to remove the fishy smell of the fish tank is to clean the filter bin, prepare a bucket of water, put the filter material in the filter bin into the bucket to explode oxygen, then clean the filter bin and white cotton, add new water, put the filter material back, and turn on the oxygenation pump.