The aquarium – which stood 45 feet tall and contained 1,500 tropical fish – caused "incredible maritime damage" when it broke, according to the BBC, quoting local authorities.
Debris from the incident was scattered across the street in front of the hotel and has since been closed due to flooding.
More than 100 firefighters were reportedly in attendance, but it is not year clear what caused the AquaDom to shatter.
The hotel – which features 427 rooms and suites across six floors – was relaunched in January of this year and became the first premium luxury lifestyle Radisson Collection hotel in Germany.
The AquaDom underwent a "thorough modernisation" prior to the opening.
