After spending over 30 years at the Inland Revenue Authority of Singapore (Iras), Mr Timothy Ng and his wife decided to set up a fish farm off Pulau Ubin in 2004.
Then deputy commissioner of Iras, he was nearing retirement and was charmed by the idea of having a floating kelong. But he did not expect what was to come.
He was affected by the algae bloom in 2015, and the oil spill this year has caused him to suspend his sales.
"I started this more as a hobby and thought it would be good if I could make money, but I didn't expect it to be this tough," said Mr Ng, 68, who is president of the Fish Farmers Association of Singapore.
His farm rears fish like groupers and red snappers, which he sells to middlemen. They, in turn, sell them to restaurants and wet markets.
This year's oil spill caused him to lose about 60kg of fish, and left the water in net cages covered with black oil about 2.5cm thick.
"The oil was so thick that the bubbles didn't even break the surface," said Mr Ng, referring to the bubbles of his cage aeration system.
In 2015, the algae blooms wiped out his total stock - or 10,000kg - of fish.
Since then, Mr Ng said, he has known of at least two farmers who have sold their businesses and others trying to do the same, or who have scaled down their production because they could not cope with the losses.
Mr Timothy Hromatka, 44, who started his fish farm off Pulau Ubin six years ago, got a new business partner to put money into his farm here after the algae blooms in 2015. He is now running a fish farm in Bali, Indonesia.
"I don't have any more money to put into the farm... The algae blooms in 2015 really shut us down. Not just in terms of monetary loss but also a loss of heart and confidence. In Bali, the waters are deeper and there have been no harmful algae blooms so far," he added.
To minimise his losses, Mr Ng said he is moving to rearing prawns, which can be sold at twice the price of seabass.
On how sustainable coastal fish farming will be, he said: "It all depends on how deep your pockets are... I've pumped in at least a million so far and I haven't made profits yet."