This is a mangrove crab. They are the largest edible swimming crabs in the world. Its habitat is the muddy bottom of estuaries, as well as coastal brackish water. It is also commonly called a mud crab. It is a pest for young plantations throughout the world due to it cutting off the stems of seedling plants.
This is a picture of a type of fish called the mud skipper. They live on mud flats on mangrove shores. They have an expanded gill chamber so when they come out of the water, they can take in oxygen. One of the mud skipper's notable features is its eyes, perched atop their heads that allow them to see under and above water. It can also camouflage.
This is the saltwater crocodile. It normally attains a size of 6 m in length and inhabits mangrove covers and swampy grasslands. It's main energy source is dead and decaying biomass and is a major scavenger of the mangrove area. It has also been known to hunt small animals and fish. It has not been classified as a threat to humans, but it is still a formidable predator.