Bug Wiki
Sticker of Great silver water beetle
Bug card No. 0660 of 1,500

Great silver water beetle

Hydrophilus piceus
Eats: A bit of everythingBeetlesPonds, rivers and shores6 legs

The great silver water beetle is one of the biggest insects that live in water. It is black with a greenish shine and has bulging eyes. It swims in quiet ponds, lakes and ditches full of plants.

Lives in
Europe, North Africa and Asia as far as India and China, in ponds, lakes and marshy ditches
Length
5 to 5.2 cm (2 to 2 in)
Top speed
about 1.3 km/h (0.81 mph)
Swimming, estimate
Can it hurt you?
Harmless
Harmless. It is not dangerous to people, so you can watch it swim.
What does it eat?
It eats many things, but it likes water plants best. Its larvae hunt pond snails and drill holes in their shells to eat them.
For real!Photo of Great silver water beetle
Picture by Darkone. CC BY-SA 2.5, via Wikimedia Commons.

How big is it?

How long is it?

Great silver water beetle about 5.2 cm long (2 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)A banana about 18 cm (7.1 in)
as long as 9 grains of rice in a rowas long as 1.5 toy building bricks in a rowcould swim the length of a bathtub in 5.5 seconds

How big is Great silver water beetle compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

How fast is it?

cool stuff

Fun facts

1

Its larvae can grow up to 7 centimetres long, even longer than the grown-up beetle.

2

In spring, the mother spins a little silk bag, fills it with eggs and lets it float on the water like a tiny boat.

3

It can live up to three years, but most die after laying eggs in their first year.

4

It has become very rare and has disappeared from some countries, like Norway.

you asked

Most asked questions about Great silver water beetle

?How big is the great silver water beetle?

About 5 centimetres long, which makes it one of the largest water insects.

?What does the great silver water beetle eat?

Mostly water plants. Its larvae eat pond snails.

?Is the great silver water beetle dangerous?

No. It is harmless to people.

For bug experts

Scientific name
Hydrophilus piceus
Group
Beetles
Family
Hydrophilidae
Classification
Insecta > Coleoptera > Hydrophilidae
Lives on
Europe, Africa, Asia

Where the facts come from

  1. Hydrophilus piceus (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Darkone. CC BY-SA 2.5, Wikimedia Commons. The round sticker of this bug is cut from the same picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

More from the same group: Beetles

Also at home here: Ponds, rivers and shores