Cods
This is a large group of fish ranging from the small, colourful basslets to the large Queensland groupers. Its a beutifull family of fish that loves playing hide and seek with the divers. Look inside caves and cracks, under ledges, or inside soft coral "trees" to find them in their hiding place. many can adjust their colour to blend in with their sorounding.
The majority of species have three spines on the gill cover and a large mouth with more than one row of teeth. Generally these fish ambush prey using their colouration patterns for camouflage. Cod are also known as Groupers. 
The most common Cod around the Whitsunday's are HoneycombCod, Coral Cod,Barramundi Cod and potato cod. Those are protected species around the Great Barrier Reef and is threatend by habitat loss. Many species of this group are of commercial value. However, fish among this group are among the worst offenders for causing ciguatera poisoning. There are size and bag restrictions for these fish within the Marine Park. All potato cod and groupers over 120 centimetres in length are protected. the big poteto cod (up to 1.8 meter!) is likely to follow your torch during a night dive and hunt little fish that comes into the light.
Sweetlips
Look for the beutifull Harlequin Sweetlips in caves, cracks and swimthroughs or under big plate coral. this is a shy fish named after his most obvious feature. if you are lucky, you might find the famous "disco dancer". those are the juvenile sweetlips, usually spotted inside a patch of staghorn coral or in any other good hiding place.they are very colourfull and they never stop moving in their flappy real quick way that looks like a crazy dance and gave them their name.
Emperors
Emperors are usually found over sandy areas adjacent to reefs where they forage for crabs, sand dollars, fish and other bottom-dwelling organisms. The Red Emperor is one of the oldest fish in the reef living up to 50 years old. Juveniles live in shallow water seagrass beds and mangroves, moving offshore as they grow. Sex changes from female to male occur as the emperor grows.