Home Bug Differences Water Bug vs Roach: Differences & Similarities

Water Bug vs Roach: Differences & Similarities

When placed together, most people can effortlessly conclude that a water bug and a cockroach are the same but slightly different insects. Truth is, these are two very distinct animals found in different biological categories. Their behaviors, habitats among other features allows one to adequately differentiate between the two. Following are the differences and similarities with pictures.

Are Water Bugs Roaches?

After taking a deep dive into various authentic resources it’s clear that in fact, water bugs are not roaches. Which also implies that roaches are not water bugs.

However, there is a type of roach, the oriental cockroach (Blatta orientalis), native to Africa, that is actually called a water bug. This roach, sometimes referred to as black beetle, prefers damp areas and in terms of appearance it is shiny and black or dark brown in color. It is just a roach called a water bug…but it really isn’t a water bug.

Oriental Roach also called water bug
Oriental roach Adult male, female, baby and eggs

Water bugs are a specially defined type of insect species that mostly live in humid and water-filled areas, hence the name. The true bugs found in the order Hemiptera are very distinct from touches in terms of appearance, behaviors, diet, and habitats. These bugs are further defined into four distinct types which are discussed in another text.

Picture of a water bug

Cockroaches, on the other hand, are not too biters. Parasitic in nature and tends to live on the low side of life minding their own business. The most prevalent type of roaches that come closest to water bugs is the oriental cockroaches. An American type that tends to dwell in damp areas.

Photo of a roach
winged cockroach


So you’ve read about the definition, let’s have a deeper look into the differences between these two types of insects.

For this phase of differences, we will use the giant water bugs, the most common type of true bugs.

Water Bugs

  • Aquatic- as the name suggests, water bugs mostly habitat in water, dampen areas and placed with a high percentage of humidity. Their bodies especially the swimmers are designed in such a way that they can swim faster than even fish.
  • Predators – they actually hunt and feed on other tiny insects. Especially if you have a pool, water bugs will tend to hand out around that area as there are plenty of tiny insects there.
  • Toe biters –  they have very painful bites, similar to wasps, except in this case they can only reach the toes.
  • They fly – especially during the mating season, they move from one water body to the next.
  • Attracted to light – whether you have pool lights or ones at the porch, these tiny critters are somewhere there hiding.
  • Large in size – especially for the giant water bugs, they are over two inches long and one inch wide. That’s a lathe size for an insect, seeing that some even measure 12 mm. Furthermore, some may even grow to over four inches long.
  • Body appearance- they are tan-brown in color and have a flattened body. The only time they have an extended body is when they’re about to fly. Plus, their antennas are found under their heads, above their eyes.
  • Survival tactics – water bugs have clawed front feet to allow then to capture their prey. They also have a short, piercing mouthpart under their heads for the same purpose.
  • Water bug babies don’t have wings hence can’t fly.


  • They live in wood – for example, the cardboard boxes, wooden cabinets, spaces and creeks on doors and other wooden surfaces.
  • They are scavengers – preying on leftovers and cramps of food left anywhere, especially eating areas like the kitchen or dining areas
  • They don’t bite unless under extreme duress.
  • They have wings but also rarely fly. They’re more of crawlers than fliers. Besides, the wings on either type of cockroaches are either small or non-existent.
  • They prefer dark and hidden areas hence very unlikely to be found where the light shines.
  • Medium in size – they would never get to the same size as the water bugs. Probably closer to an inch.
  • Appearance – they’re body shape is oval with body parts asymmetrical to each other. They have very long antennas similar to the length of their bodies, and a hairy appearance thanks to its six legs covering the spine.
  • They have a downward-facing head which you can hardly see unless you go looking.

Well, there you have it, water bugs and cockroaches are actually very dissimilar to each other. From their appearance, how long they grow, where the head is located, the size of the antennas, these two critters have different looks.

Their habitat too, what belongs to the water, stays in the water and the cockroaches stay on land specifically where there is a woody smell or wood shavings.  Although the water bugs can live on land and the roaches can survive in water, that’s not their original home.

They have different diets. The cockroaches are not selective in nature, they feed on what they find from cramps, leftovers, and garbage. Water bugs, however, go hunting for their insect of choice. Their bodies are mechanized in a way that they can easily target prey and attack. Their hind feet tend to paralyze their prey using a liquefied enzyme found on their proboscis.

Behaviors are also very different in that the water bugs love to be seen. Whenever there’s the light they will walk across the light and just stuck around.

The cockroach, however, loves dark and hidden areas like the wooden cabinets, the attic where people rarely visit. This also leads to the water bugs having to defend itself constantly hence the tendency to bite which is unlike the cockroaches.

Lifespan with and without food

A roach can live for a whole week without taking water. It can also live for a month without food. Different types of roaches vary in their life span living up to an average of 12 months. American roaches live for about one year while German roaches live for about 100 days. Roaches feeds on anything hence starving them to die may not be a better way of eradicating them.

Water bugs live anywhere for a period of 1 to 4 years. They can live for 2 weeks without water and 4 weeks without food. Its life span is shortened by breeding. An increase in reproductive effort results to less energy to maintain body tissues resulting to a shorter life span. According to Gilg Mathew, an American Midland Naturalist, male and female water bugs that are virgins live longer than those that breed as elaborated by.

Finally, cockroaches are a true definition of pests, they have parasitic features that highly depend on humans, water bugs however simply hunt for themselves and can survive without humans.


There are similarities between these two insects. In terms of appearance, they somewhat look the same. The brown tan color or reddish-brown hue they have in their bodies makes them seem similar – especially when you find one lurking on the inside of the house.

Both of them have parental care, water bugs come together in time of breeding while roaches also prefer being surrounded by other roaches.

They have similar habits of entering the home through cracks, holes or pipes that lead to the house and exit through drains. They both react and fear human beings by biting them or hiding away from them.

They’re also full-bodied. The water bug may be long but in terms of height, they’re very close to the ground, similar to the cockroaches. Their flying mechanism is somewhat limited to specific species of cockroaches. You already know that adult water bugs fly, but very few cockroaches fly or use their wings at all.

When you see water bugs and roaches, you would gladly classify one with the other, but when you look at them intently, you will notice that they are actually very different creatures. They behave differently, they’re adapted differently and have very different characteristics.

Further Reading


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