water bug

US /ˈwɑː.t̬ɚ ˌbʌɡ/
UK /ˈwɑː.t̬ɚ ˌbʌɡ/
"water bug" picture
1.

Wasserkäfer, Wasserwanze

any of various insects that live in or on water, especially a large aquatic bug (family Belostomatidae) that can inflict a painful bite

:
I saw a large water bug swimming in the pond.
Ich sah einen großen Wasserkäfer im Teich schwimmen.
Some people confuse cockroaches with water bugs.
Manche Leute verwechseln Kakerlaken mit Wasserkäfern.