Is fish bone biodegradable? (3 classes of fish)

This article shall look at the biodegradability of fish bone.

It shall also cover other areas such as:

  • The advantages of fish meal as a fertilizer.
  • The classes fish.
  • Nutritional benefits of fish.
  • Eco-friendliness of fish bones.

Is fish bone biodegradable?

Yes, fish bone is biodegradable. Fishbone is a natural product that is susceptible to microbial degradation.

It is estimated that fish bones are degraded faster than the bones of other animals.

Biodegradation is the process by which naturally occurring organic materials are broken down by microorganisms such as bacteria and fungi into small particles which are not harmful to the environment.

Biodegradation is carried out by different agents such as UV radiation, light, wind, and water but the most effective agents of biodegradation are bacteria and fungi.

Biodegradation occurs in three distinct stages: biodeterioration, bio-fragmentation, and assimilation.

The biodeterioration process loosens up the structure of the organic substance. For instance, the cell wall of plants is weakened by light, wind, water, and UV radiation.

Bio-fragmentation involves the breakdown of organic matter into smaller, nontoxic particles by bacteria and fungi, releasing water and carbon dioxide in the process.

Assimilation is the last stage of biodegradation and it involves the microorganisms taking up the products of bio-fragmentation into their biological machinery to be used to make energy.

Biodegradation can either involve the microorganisms using oxygen, aerobic biodegradation or it can involve the microorganisms which do not use oxygen, anaerobic biodegradation.

What are the classes of fish?

There are different classes of fish depending on their body characteristics.

Some fish do not have bones but cartilage while others are said to be bony.

Here are the classes of fish.

  • Superclass agnatha.
  • Chondrichthyes.
  • Osteichthyes.

Superclass agnatha.

This is a class of fish that are said to be jawless. The fish are in the phylum Chordata and that means they have a backbone.

The class consists of some extinct fish species.

The existing examples include the lamprey, lancelets, and hagfish.

The agnatha fishes lack fins and scales and their bodies are covered by skin.


This is a group of fish whose skeleton is made up of cartilage instead of bones.

The fish in this class have jaws and fins unlike their counterparts in class agnatha.

This is class of fish is divided into two:


This is a class of fish that contains the likes of sharks, rays, skates, and sawfish.

These fishes lack the swimming bladder, they maintain buoyancy using oil stored in the liver. They have a series of sharp teeth.


This subclass contains fish like ratfish of genus chimera and elephant fish of genus callorhinchus.

These fishes are peculiar in the sense that they lack a stomach, and their food goes directly to the intestines.


This is a class of fish whose skeleton is made up of bones. The fish in this class are also called bony fish.

This is a very diverse class that contains close to 28,000 species of fish. Most fish types fall in this class. It is the largest class of vertebrates.

The class is subdivided into:

Actinopterygii- This class comprises ray-finned fishes. Their fins are webs of skin supported by bony or horny rays.

Sarcopterygii- This class comprises lobe-finned fishes. The fins are joined to the body by a single bone.

The fins of lobe-finned fishes differ from all other fishes in that each fin is emanating from a fleshy, lobe-like, scaly stalk extending from the body.

What is the nutritional value of fish?

Fish is one of the most consumed sources of proteins.

There are different types of fish consumed, such as tuna, mackerel, sardines, salmon, catfish, lake Victoria perch, haddock, and many others.

Other than proteins, fish meal contains the following nutrients.

  • Fats: fish oils contain two main fatty acids, eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA). 
  • Cholesterol.
  • Vitamin B-12.
  • Phosphorus.
  • Selenium.

The Omega-3 fatty acid in fish has a lot of advantages which include:

  • Omega-3 fatty acid (docosahexaenoic acid) helps in reducing systemic inflammation and also lowers the risk of cardiovascular disease.
  • Omega-3 is also said to prevent cancer and arthritis.
  • Omega-3 reduces the risk of autoimmune disease.
  • It protects one’s vision in old age. Age-related macular degeneration (AMD) leads to vision impairment and blindness in older people. Omega-3 is believed to prevent this condition.
  • Omega-3 is said to fight depression and increase the effectiveness of antidepressants.
  • Omega-3 helps in the development and healthy functioning of the brain.
  • Omega-3 is also believed to prevent bipolar disorder.

Other nutritional advantages of consuming fish are:

  • Vitamin D in fish could help to improve sleep as some types of insomnia have been linked to vitamin D deficiency.
  • Some studies have shown that fish consumption reduces the risk of asthma in children.
  • Vitamin D has been attributed to the prevention of autoimmune diseases such as diabetes type 1.
  • Vitamin D and Phosphorus in fish help in bone development.

What is the importance of a fish-bone meal to animals?

Fish meal is one of the most popular diets for animals such as swine and dogs.

The bones of fish are very rich in calcium and phosphorus. These two elements are very essential for the healthy growth and development of animals.

The efficiency of mineral absorption depends on the concentration, the ratio of the diet to other diets, and the source of the mineral.

Calcium and phosphorus play big roles in the development and healthy maintenance of the skeletal system, and the control and regulation of clotting and muscle contraction.

Deficiency in calcium leads to improved bone formation, reduced bone strength, lameness, and poor general body growth. The deficiency of calcium and phosphorus is evident in young animals such as pigs through rickets.

In swine, when calcium in the diet is low, they remove calcium from their bones to make milk, this weakens the bones, leading to a “downer” condition.

Phosphorus is important for proper mineralization in skeletal muscles. It is also an essential element in the formation of energy, ATP, and as such, it is found in all energy synthesizing cells.

It is also an important ingredient in the formation of cell structures such as cell membranes, phospholipids, and the phosphorylation for enzyme activation.

How is Fish meal an organic fertilizer?

Fish meal is used as an organic fertilizer. It is rich in nitrogen and phosphorus.

These two elements are very important for crops.

Nitrogen is an important plant macronutrient that plays several roles in plants.

  • It is a component of amino acids that form proteins.
  • It is the building block of plant enzymes.
  • Nitrogen helps in the healthy growth and development of plant tissues.
  • Nitrogen helps the roots in the absorption of water and nutrients.
  • Nitrogen is essential for the proper transportation and excretion of plant substances.
  • It is essential in the making of chlorophyll.

Phosphorus is equally important in the growth and development of plants.

  • It is involved in energy transfer in the form of ATP.
  • It helps in the process of photosynthesis.
  • It helps in the transformation of sugars and starches.
  • It helps in the movement of nutrients in the plants.
  • Phosphorus is an integral part of plant DNA and RNA.

What are the health hazards associated with the fish meal?

Fish meal is a very nutritious diet but it has some disadvantages which include:

  • Fish bones can cause choking and airway obstruction if swallowed.
  • Ingested fish or vapor from a fish meal can cause some allergic reactions in some people. Such reactions include; urticaria, angioedema, and distributive shock.
  • A fish meal may contain biotoxins which they use against predators. They also contain toxins acquired from feeding algae. These toxins may lead to food poisoning.
  • Some fish may contain heavy metals such as mercury and lead which are toxic to humans.

Is fish bone eco-friendly?

Yes, fish bone is one of the most biodegradable bones in nature. Fishbone is broken down by bacteria and fungi to produce water and carbon dioxide.

According to a study, fish bones are also rich in nitrogen, phosphorus, and calcium, these elements form the crop’s essential nutrients.

There should be controlled disposal though, to prevent over-accumulation of fish bones in the environment.


This article has answered the question of the biodegradation of fish bone.

It has also covered other areas such as:

  • The types and classes of fish.
  • The nutritional value of fish.
  • The nutritional value of the fish meal to animals.
  • The importance of fish meal fertilizer to plants.
  • The eco-friendliness of fish bones.

For any questions or comments please use the comment section below.

Frequently Asked Questions (FAQs): is fish bone biodegradable?

Can you compost cooked fish bones?

Yes, fish bones can be composted because they are susceptible to fungal and bacterial degradation.

Are fish bones good fertilizer?

Yes, grounded fish bones are good fertilizers. They are rich in nitrogen, phosphorus, and calcium, elements that are very essential to plant health. 


Abdelhamid, Asmaa S; Brown, Tracey J; Brainard, Julii S; Biswas, Priti; Thorpe, Gabrielle C; Moore, Helen J; Deane, Katherine HO; AlAbdulghafoor, Fai K; Summerbell, Carolyn D; Worthington, Helen V; Song, Fujian (2018-11-30). “Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease”. Cochrane Database of Systematic Reviews. 11: CD003177. doi:10.1002/14651858.cd003177.pub4

Helfman, G.; Collette, B.; Facey, D. (1997). The Diversity of Fishes (1st ed.). Wiley-Blackwell. ISBN 978-0-86542-256-8.

Andres Donoso-Bravo et al.- Water Sci Technol( 2015). Anaerobic biodegradability of fish remains experimental investigation and parameter estimation.

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