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Where does nitrogen in aquarium fish food come from and what effect does it have on water quality?
Nitrogen is one of the key elements naturally found in all aquarium fish food. Although it's often associated with ammonia in the tank, its presence in food is actually completely natural and essential. In this article, I explain where nitrogen comes from, how fish process it, and how it impacts the health of your aquarium.
- Why is there nitrogen in food at all?
Nitrogen is a basic building block proteins, the most important nutrient in fish diets. Each amino acid – the building block of protein – contains nitrogen atoms in its structure. Therefore, in practice:
The more and the better the quality of protein, the more natural nitrogen in the food.
This is not artificially added nitrogen – it comes exclusively from protein raw materials.
- Natural sources of nitrogen in fish food
Nitrogen appears wherever protein is present. In extruded fish food, these are most often:
- premium fish meal (60–72% protein)
- krill meal
- shrimp meal and other crustacean raw materials
- algae, including spirulina (55–65% protein)
- vegetable protein concentrates (e.g. soybeans, peas)
- insect proteins (e.g. Hermetia illucens)
All of these ingredients naturally contain nitrogen because they are rich in amino acids – the basic building blocks of fish muscles, enzymes and hormones.
- How do fish metabolize nitrogen from food?
Fish use some of the protein for growth and regeneration, while the rest is metabolized. The result is:
- ammonia (NH₃ / NH₄⁺) – the main nitrogen product excreted by fish,
- urea (to a lesser extent in some species).
It is these metabolites that end up in the water and can affect the parameters of the tank.
- Does nitrogen in feed always worsen water quality?
Not necessarily. The key isn't the amount of nitrogen itself, but:
👉 Protein digestibility
The more digestible the protein, the:
- more nitrogen is used by the body,
- less ends up in the water as ammonia,
- we get better growth with less waste.
Premium extruded foods, such as formulas such as Premium Daily Food, are characterized by very high digestibility thanks to:
- appropriate temperature and pressure during extrusion,
- initial protein denaturation,
- reduction of anti-nutritional substances (e.g. in soy).
👉 Type of protein
Animal proteins (e.g. fish, krill) have an amino acid profile closer to the needs of fish than most plant proteins – so they are better utilized and leave less waste in the water.
- How does food quality affect aquarium stability?
High quality and digestible ingredients mean:
- lower ammonia production,
- less filtration load,
- slower increase in NO₂ and NO₃,
- cleaner substrate and less detritus,
- better colors and condition of fish.
Therefore, premium foods not only support animal health, but also directly impact the quality of life in the entire aquarium ecosystem.
- Nitrogen and the extrusion stage – what does the technology change?
Extrusion process:
- does not remove nitrogen,
- but by improves its biological availability,
- reduces the amount of indigestible fractions,
- stabilizes food,
- ensures proper buoyancy of the granules.
This makes extruded foods more nutritionally effective and less burdensome for filtration.
- Summary
Nitrogen in food is not a threat - it is a natural and essential element of proteinThe only problem may be:
- low protein quality,
- low digestibility,
- overfeeding.
By choosing extruded foods based on high-quality protein raw materials (e.g. fish, krill, algae), we significantly reduce the amount of nitrogen entering the water, thus improving the stability of the entire aquarium.
