In nature, bacteria can hardly be surpassed in terms of diversity. However, they are so small that we cannot see them with our eyes.  

As invisible pathogens, we humans are very suspicious of them. It was only modern molecular biology that showed us that they are necessary on the skin and intestines to maintain our health.  

Bacteria are also indispensable in food production and processing. Certain types have long been used to make foods such as cheese, sourdough bread, and sauerkraut.  

But what role do bacteria play in fish farming, especially in closed aquaculture systems? 

Bacteria In Aquaculture 

Bacteria can only multiply if they are given food. Since their food is often little residues, this is hardly noticeable: residues disappear, but a pile of bacteria remains.  

In aquaculture, bacteria use leftover feed, for example. However, they mainly live in and off the excrement of the fish.  

As in nature, they “remineralize” the animal excretions, some of which are poisonous, by breaking down the original organic feed components to such an extent that ultimately only CO2, H2O and various inorganic substances (phosphate, ammonium, nitrate, atmospheric nitrogen) remain.