The thieves forced their way through the metal security fencing equipped with nets, bags and buckets, ripped the burglar alarm out and stole more than 30 of the most expensive fish.

An estimated £10,000 of damage was also caused to the Japanese Water Garden on Toton Lane during the break-in at midnight on Monday.

Director, Wendy Langford, said: "I was just amazed. The first thing I saw was there was hardly any water left in the main pond, which is where the most expensive fish are kept. They'd drained it with our pump to make it easier to catch the fish.

"The pond that is usually five to six foot deep was found just a foot-and-a-half deep in water.

Mrs Langford added: "They must have been a professional outfit because they knew what they were doing. It all seemed very organised and I would imagine they would have been here quite a while.

"It was just disbelief at all the mess. I could see the damage to the fencing as I pulled in so it was obvious there was a problem.

"I know they came with nets because they left them here.

"I think they used crow bars and sheer brute force to get in, because we found some crow bars on the floor.

"Various different granite ornaments were smashed and we've got to change the padlocks and all sorts but I think they knocked things over in their struggle to get in, I don't think they came to cause damage."

Staff at the store discovered the break-in when they arrived at work on Tuesday morning. Police spent the day at the centre gathering forensics.
Staff have given officers pictures of the fish and feel confident they would be able to easily identify them.

Anybody with any information should call police on 0115 967 0999.