This research conducted in 2019 at the University of Guyana investigated the content of methylmercury in local food fish Macrodon ancylodon locally known as Bangamary. A total of 24 samples of M. ancylodon was purchased from the Meadow Bank Wharf in Guyana for analysis of total mercury level. Additionally, the size frequency at which mercury concentration is the highest was also evaluated. The results indicated that total mercury concentration in each sample of M. ancylodon was less than 0.5 mg/kg. With an average total mercury content of 0.10 mg/kg, adults had the greatest total mercury content, followed by juveniles (0.06 mg/kg) and young (0.02 mg/kg). This may be attributed to the carnivorous diet of M. ancylodon and the fact that the fish species is usually captured in the estuarine regions of the Demerara and Essequibo Rivers. These waterways are linked to mining areas in Guyana's interior region that discharge mercury contaminated water, which could be the reason why mercury is bioaccumulating in the tissue of the Bangamary.