A US company that helped build a huge aquarium in Berlin says it is sending a team to investigate the rupture of the tank, which sent a wave of debris, water and tropical fish crashing through the hotel reception it was located in and on to the street outside.

Reynolds Polymer Technology, which says it manufactured and installed the cylinder component of the aquarium tank 20 years ago, said in a statement that “at this point, it is too early to determine the factor or factors that would produce such a failure”.

Police have said they found no evidence of a malicious act but the cause of the spectacular collapse shortly before 6am on Friday, in which two people were slightly injured, remains unclear.

Berlin’s top security official, Iris Spranger, told German news agency dpa on Friday that “first indications point to material fatigue”.

Officials said on Friday that the hotel building itself was assessed to be safe.

The local government said that nearly all of the 1,500 fish that were inside at the time of the rupture died but “a few fish at the bottom of the tank” were saved.

About 400 to 500 mostly small fish from a separate set of aquariums housed under the hotel lobby were evacuated to other tanks in a neighbouring aquarium that was unaffected.

The aquarium opened in December 2003 and was modernised in 2020.

Reynolds Polymer, based in the US, which says on its website that 41 of its acrylic panels were used in building the tank cylinder, said it “offers its sincere concern” to the hotel guests and workers who were affected and to those who were injured.

It said that “we are also deeply saddened by the animals and aquatic life lost”.