Two Fire Service staff were attached to the Dhaka directorate for attempting to snatch Hilsa from fishermen.
Farid Ahmed, Deputy Director of Chandpur Fire Service and Civil Defense, said they investigated the incident and immediately informed the higher authorities.
Official steps were taken against accused diver Humayun Ahmed, 29, and fireman Liton Dey, 28, he said.
Further steps will be taken against them after forming a probe body.
On October 29, Humayun and Liton reportedly identified themselves as policemen and tried to snatch Hilsa from fishermen 12 Chandra Union under Chandpur sadar upazila.
They were reportedly beaten up by locals.