Plenty of Fish has become the latest high profile hacking casualty after the dating site's database of usernames and passwords was compromised.

Fish’s security breach follows that of trapster, a mobile application for speed cameras and the blog network Gawker, which both already suffered similar breaches.

Analysts point out that the latest hack reinforces the need for users to use different passwords for different sites to prevent their online estates from becoming compromised.

News of the breach emerged after Fish founder, Markus Frind, wrote a blog post claiming that he had been the victim of extortion from an Argentinian hacker, with links to the Russian mafia, Chris Russo.

Frind admitted: “I think a slept a total of 2 hours a night for a week….. Plentyoffish was hacked last week and we believe emails usernames and passwords were downloaded. We have reset all users passwords and closed the security hole that allowed them to enter.”