Normally you brush your teeth after you've eaten fish, but it seems one trout decided to eat a toothbrush instead.

A late-evening snag on Lake Tikitapu (Blue Lake) in Rotorua landed keen fisherman Alfred Hoyle a 2kg rainbow trout recently, and while gutting it, he felt a "particularly hard lump" in the stomach of the fish. He slit it open - only for the head of a toothbrush to pop out.

Amused at first, Hoyle said it was the reality of such a popular lake, and that campervan users may be the culprits.

"They come and brush their teeth and get water from the lake," he said.

Lake Tikitapu. Photo / Supplied
Lake Tikitapu. Photo / Supplied

The popular lake was Hoyle's favourite fishing spot, and despite this being his most unusual find, he was never surprised by what he found in, or on, trout.

Once, it was a colourful elastic hair band, which had wrapped around the trout just behind the gills, something it probab ly slipped into as an alevin (young trout).

But he was not concerned by the bits and pieces pulled out of the lake, saying it was generally clean, given the numbers of people who visited it in summer.

Lake Tikitapu. Photo / Supplied
Lake Tikitapu. Photo / Supplied

Rainbow trout usually reach 1-2kg in weight but in larger rivers and lakes, where food is abundant, they may reach 5kg or more.

They are common in rivers and lakes but not as widespread as brown trout.