Owner Sarah Thornton, 44, said she was “devastated” at having to shut down her dream business.
She began work to turn the building at 19 Pitsford Street, Hockley, into a restaurant in April last year and opened to the public in August.
But she has not traded since just before Christmas, despite Fishylicious ranking 244 out of 1880 restaurants in Birmingham on TripAdvisor - far higher than Harry Ramsden's before it closed earlier this month.
Sarah blamed alleged damp for the decision and said: “It’s heartbreaking.
“We took it on last year, but when the weather started turning, the building did as well.
“It would be dangerous for customers to eat here, especially as it has affected the kitchen.”
Having signed a ten-year lease on the building, Sarah said the matter was now in the hands of her solicitor.
“The building itself is only a few years old because I understand the one that used to be here burned down,” she said.
“I had a bit of money from my father’s inheritance and put that towards the more than £50,000 it cost to set up the business, though it would have been twice that if I hadn’t had so much help from friends and family.
“The cost of trying to make the building usable again would be a lot more than £10,000.
“I’ve been told that all of the plumbing, electrics, alarm and CCTV would have to come out for work to be done and then it would all have to go back again.”
Sarah, who employed three staff, said she first realised there was a problem last September.
“I started to notice there was something wrong with the chimney breast,” she claimed.
“Every time we tried to do any repairs, the damp would come back through and the damp is now affecting all four walls in the restaurant and kitchen.
“I served the last meals on December 23.
“I didn’t want to be open over Christmas because you can’t get fresh fish.
“But before that the business was strong and getting better.
“Our plan for this year was not to be closed but to develop our advertising, website and create a beach outside so that people could imagine they were at the seaside.
“ I couldn’t risk the restaurant being closed on public health grounds, so I went to the city council and told them I was closing and why – the worst thing would have been for them to come and close me down.”
She added: “Now I’m stuck and having to pay for things like insurance and my car with no income from the restaurant.
“Even if work started today, it would be four months before we could reopen and it would be like starting all over again a year after starting the first time.”
Sarah went to Bartley Green Girls’ School before working at TGI Fridays on the Hagley Road.
A mixture of theatre, retail and estate agency jobs eventually led her into the pub trade via the Actress & Bishop .
“Because this building was so new, I was assured it was sound,” claimed Sarah.
“I didn’t have a full structural survey done as I would have done if I had been buying it and not leasing.
“We spent almost £10,000 on the kitchen alone and even made our own tables by recycling Jewellery Quarter roof joists.
Renowned graffiti artist Temper also spray painted a stunning mural on the doors to emphasise the restaurant’s nautical, independent theme and Fishylicious had its own-label vinegars, too.
When the Birmingham Mail contacted the landlord, Umar Ahmed, he said: “The matter is in the hands of my solicitor.
“It was an empty commercial building ready for rental.”
Mr Ahmed said he would supply the Mail with his solicitor’s number after 20 minutes, but put the phone down when then asked how long he had had the building.
When a reporter repeatedly called back the phone rang out and did not take messages.
You can read our first review of Fishylicious - conducted when it opened - by clicking here .
Why fish - and why Fishylicious?
With its aquatic blue colour, a logo that crosses a fish with a fork and noisy gulls living in the Jewellery Quarter, Fishylicious isn’t as far from the seaside as it might seem.
Sarah said: “I love fish but it’s hard to get decent fish and chips, so that’s what I wanted to make.
“I felt really proud because I was doing something I loved that was mine.
“We were looking at having DJs on the beach at the weekend as we are only surrounded by a train station, wasteland and a cemetery.
“It would have been brilliant this year for the kids.
“Whether it’s here or somewhere else, I still want Fishylicious to succeed.
“At the moment it’s really hard to think I have to take everything out of here to get it stacked and stored before even considering the possibility of starting again.
“I am devastated and it’s hearbreaking.”
Fishylicious is the second fish restaurant to close this year
The closure of Fishylicious comes just after the 120-cover Le Monde fish restaurant closed in Brindleyplace at the end of 2016.
Le Monde’s director Bob Norton said a number of factors had affected his business, including not having the economies of scale of a chain, trying to compete with fast food outlets and traffic chaos around the redevelopment of Paradise.
Read the full story of the Le Monde closure here and to watch a video of US guitar legend Brooks Williams playing there.