Difference between Blood and Haemolymph


Blood is a red coloured fluid that circulates through the entire body in vertebrates. It can also be considered a tissue because it contains different cells such as red blood cells, white blood cells and platelets. It transports oxygen and nutrients to all the parts of the body.

Read about blood and its composition here.


Haemolymph is the analogue of blood flowing in invertebrates, mostly arthropods. It fills the cavity (haemocoel) of these organisms. Unlike blood, haemolymph does not carry haemoglobin and hence does not transport oxygen. It contains cells called haemocytes.

The haemolymph is mainly composed of water, but it also comprises inorganic salts, amino acids, proteins, and other organic molecules. The haemocytes have a huge role in the immune system of arthropods.

Blood vs Haemolymph




It is a fluid that circulates throughout the body in the circulatory system.

It is the fluid that fills the cavity (haemocoel) of invertebrates.


It is composed of plasma, red blood cells, white blood cells and platelets.

It is mainly water, including inorganic salts, proteins, amino acids, and organic constituents.




Transport of Oxygen

The main function of the blood is to transport oxygen to all the cells in the body.

Oxygen is transported via the tracheal system.

Presence of Haemoglobin



Contact with Tissues

Blood does not have contact with the tissues.

Haemolymph is in direct contact with the tissues and lubricates them.


It contains haemoglobin (iron-based) that gives blood the red colour.

It contains haemocyanin (copper-based) that gives haemolymph its colour.

Explore BYJU’S Biology to learn more interesting topics.

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Frequently Asked Questions on Difference between Blood and Haemolymph

Why is haemolymph not considered blood?

The chief components of blood, haemoglobin and red blood cells that are responsible for the transport of oxygen are not found in the haemolymph. This is the reason why haemolymph is not considered as blood.

What’s the difference between haemolymph and haemocoel?

Haemocoel is the primary cavity present in invertebrates, whereas haemolymph is a fluid that fills the cavity.

Is haemolymph extracellular fluid?

Yes, haemolymph is extracellular fluid.

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