District Police Chief Supt Peter Umbuas said the man had been remanded for four days beginning Thursday to assist in the probe under Section 304A of the Penal Code for causing death.
The boy identified as Muhammad Arhidar Abdullah was travelling in a boat with three others including the boat skipper, when their boat collided with a boat transporting 10 China tourists at about 3.10pm.
The boy's body was retrieved at 5.44pm after three hours by search and rescue teams led by the Fire and Rescue Department assisted by other agencies.
Three others on the speedboat, Juliman Rasis, 24, Mohamad Rijal Rano, 12 and 41-year-old Jaafar Bakial sustained serious injuries.
All three were rushed to the district hospital.
Umbuas said the incident was reported by the boatman who was operating the boat boarded by 10 China tourists, comprising five men and five women from Mataking Island to Semporna. Together with them was one boat crew.
"The man said they were heading towards the mainland prior to the collision, he claimed to be unaware of the speedboat which suddenly appeared in front of his boat and that all his passengers escaped unscathed except for those on board the speedboat," said Umbuas.
"The boatman said he did not notice the speedboat which came from the right side due to the sun's glare and that he only realised there was a boat when it was just five metres away resulting in the collision.
"This prompted them and other crew to rush to the victims' aid, pulling them into their boat," said Umbuas.
Meanwhile, District Fire and Rescue Department Chief Fazizul Hizam Borhan said a 3.12pm distress call prompted seven personnel to the scene together with an Emergency Medical Response Services ambulance and a rescue boat.
He said the search and rescue operation also involved the marine police and the Malaysian Maritime Enforcement Agency, adding that the operation ended at about 5.52pm with the discovery of the boy's body. - Lagatah Toyos