A comparative study of quality of tilapia (Oreochromis mossambicus) Maldive fish with traditional tuna (Katsuwonus pelamis) Maldive fish and a comparizon of the proximate composition of raw fish and Maldive fish prepared from tilapia (Oreochromis mossambicus and Oreochromis niloticus) and tuna (Katsuwonus pelamis)