The residents are mud crabs, or mangrove crabs.

And the “condominium” array was designed for city folk who want to be farmers but lack that crucial resource of real estate.

Musa, 59, has grown mud crabs in the array for the past 20 years. Up to 35 crabs can be housed in the contraption.

“This crab condo is perfect because it is compact in size and easily managed. It also saves water as it has its own filtering system,” he told FMT at his home in Kampung Ujong Pasir here.

Musa said there is high demand for the crabs and the business is highly profitable. They fetch between RM60 and RM65 per kilogram.

His passion for urban farming led him to quit his job with an international company in Port Klang, where he was responsible for treating water to be re-used in 1998.

He then began to work on his “crab condo”, an invention that he hopes to sell to other crustacean enthusiasts.

Musa has invested up to RM100,000 in research and is preparing a working paper to protect the design and intellectual property. Unfortunately, the idea was “stolen” by one of his customers, he said. While he was left disappointed, it did not deter him.

He has since sold over 100 of his crab farms, at between RM2,500 and RM6,000 each. “I’ll never give up and will continue investing,” a determined Musa said. “After this, I’m coming up with a system to rear lobsters.”