Cockroach vs Water Bug: Difference and Comparison

In our daily life, we notice tons of insects, animals, birds, and other organisms roaming around in the open environment.

While many of us happen to be aware of many of these organisms in their correct sense, certain such organisms can confuse people to a huge extent because of having certain similarities in their appearance.  

Cockroaches and Water bugs are two such insects that people understand interchangeably and get confused about.

While both of these appear similar in their outer look, they carry a lot of significant differences in many aspects. 

Key Takeaways

  1. Cockroaches are found in dry areas, while water bugs prefer aquatic environments.
  2. Water bugs have a more painful bite and prey on other insects, whereas cockroaches are scavengers.
  3. Cockroaches possess flattened, oval-shaped bodies, while water bugs have wider, more elongated bodies.

Cockroach vs Water Bug 

Cockroaches are about 1-1.5” in length, while Water bug cockroaches are about 2” in length. Cockroaches prefer to be on land, while water bugs prefer to stay in water. Cockroaches aren’t picky eaters and easily eat from garbage, and don’t hunt, water bugs, on the other hand, are hunters.

Cockroach vs Water Bug

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A cockroach, on the one hand, happens to belong to the order Blattodea and is the main insect found on land almost everywhere on the earth.

This insect can have a size of up to 1.5 inches usually, but there is no definite size limit as the color and size of this insect can differ from species to species.

This can be found in humid places because it likes to hide in such places to feel the warmth of the earth.

To survive, this insect feeds on almost everything that comes in its way, be it a plant, a smaller insect, or any leftover food. 

But on the contrary, a Water bug is another kind of species of insect as it is found in water rather than land.

It can be noticed in many water bodies across the world and carries a similar appearance to cockroaches.

This is the reason behind the confusion of many people between a cockroach and a water bug. It happens to be bigger in size and even more dangerous than the cockroach, as it can bite humans also.

To survive, this insect feeds upon smaller insects found in the water and uses a very powerful liquid built inside its body to kill its prey. 

Comparison Table

Parameters of Comparison Cockroach   Water Bug 
Meaning  It is an insect found on land with large antennas and a flat body. it can be any type of bug found in water that stays in the water and feeds in water, and carries long legs that help it in swimming. 
Another name  Also known as American roach or roach. Also known as a true bug. 
Order  Belong to the order Blattodea. Belongs to the order Hemiptera. 
Found in It wanders on land and stays in a humid atmosphere. It wanders inside water and stays in it only. 
Nature  It has a nature of a scavenger as it can feed upon almost anything. It owns a nature of a hunter because it hunts its prey. 
Size   Up to 1.5 inches generally. Up to 2.5 inches generally. 
Harm to humans It rarely causes any harm to humans. It can bite humans and leave a nasty bite behind.  

What is Cockroach? 

Popularly known by another name Roach, a Cockroach can be described as a species of insect that is found on land all over the world. It belongs to the same order to which termites belong.

That is the order Blattodea. They have more than 5000 varieties ranging between different sizes, colors, and lifestyles. 

A cockroach happens to be adaptive towards climate and can survive in almost any weather condition.

Looking at the structure of this insect, it carries two large antennas on its head and looks like a flat shaped insect. It is seen in many households, and sometimes it is categorized as a pest

In the normal course, it happens to exist in the size of almost 1.5 inches. This insect happens to be very fond of humid and warm temperatures, and therefore it prefers staying in inner areas.

To survive, this insect feet up on almost everything that it can find easily. It can be fungi, algae, leftover food, smaller insects, etc. 

This insect does not cause any direct bodily harm to humans, such as bite marks, etc. but can be responsible for certain medical complications in the place where they are found due to poor hygiene.  


What is Water Bug? 

Found in numerous water bodies, a water bug happens to be an insect in the world of water only.

Almost 2000 species of this insect are found all over the earth, and they all differ from one another in terms of their colors, sizes, and patterns of living. 

It has a cockroach-like structure but lacks direct antennas. It has very wide legs that have a great grasp over the water. These help the water bug in its swimming activities across the water.

In most cases, this insect happens to exist in black color. It is a size of almost 2.5 inches. 

It feeds upon small insects, fishes, amphibians, etc., to survive. The body of this insect carries a very special enzyme that helps this insect in finding food.

Basically, this insect injects this enzyme somehow into the body of its prey resulting in liquifying the body of the prey. 

However, a drawback associated with this insect is that it can sometimes bite humans as well and leave a nasty mark behind. In its social life, it prefers to stay without the company.  

water bug

Main Differences Between Cockroach and Water Bug 

  1. The cockroach is an insect found on land with large antennas and a flat body. While a Water bug can be any type of bug found in water that stays in the water and feeds in water, and carries long legs that help it in swimming. 
  2. The cockroach is known as the American cockroach or roach, while the Water bug is known as the true bug. 
  3. The cockroach belongs to the order Blattodea, while the Water bug belongs to the order Hemiptera. 
  4. The cockroach stays on land while the Water bug stays in the water. 
  5. A cockroach happens to be harmless to humans, while A Water bug can be harmful. 
Difference Between Cockroach and Water Bug

Last Updated : 30 July, 2023

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