The fish were biting on Saturday morning for day one of the Cressy Trout Expo, before the rain started pouring in the afternoon.
A dry Sunday is predicted for day two of the expo, where participants will try and catch tagged Teddy the Trout.
Released on Friday night, Teddy will net the person who catches him $10,000 - although the tagged fish has only been caught on two occasions over the past 13 years of the festival.
One hopeful this year is Penny Coyle, 65, who lives out of her van and travels the country with seven fishing rods in tow.
"I'm a migratory gypsy - I come to Tassie five months over summer, and then go back to the mainland.
"I go wherever, I don't plan, and there's lots of fishing.
"You wouldn't believe how many male and female singles are doing this, because it's a magical lifestyle."
Richard Goss, who heads up the 50 volunteers that make the expo possible as president of the Cressy Trout Expo Committee, said there were more people so far than in previous years.
Meanwhile, the government will put $200,000 into expanding the Anglers Access Program, Minister for Primary Industries and Water Guy Barnett said, making it easier to access waterways for fishing.
"The next stage of the program has commenced with works to improve access for anglers along the Meander River now underway," he said.
"The program has projects covering more than 300 kilometres of river throughout the state."
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