Policemen arrested a restless visitor to the swimming pool in Velbert, North Rhine-Westphalia. In order to capture the man, the officials themselves had to go into the water.
The 32-year-old had previously behaved unusually aggressive, insulted staff for no reason and ignored a ban on bathing water, police said.
When the man finally attacked the summoned officials and retreated to a large swimming pool after using pepper spray, three policemen borrowed swimsuit on Sunday and went into the water himself.
The officers overwhelmed the swimmer for further attacks, handcuffed him in the water and arrested him. The mission had "nothing to do with carnival" had - the arrest was not possible under other circumstances, they said.
The mentally disturbed 32-year-old was taken to a psychiatric hospital. The bathing in the swimming pool could be continued undisturbed police.