Mangroves are fascinating environments. Usually murky in the Darwin region, the water clarity and salinity can change rapidly with tide and rainfall. The fish that live in it are remarkable.
Above is the Mangrove cardinalfish (Apogon hylasoma). Known sometimes as a “gobbleguts” this fish simply inhales other fish. When breeding time comes around, males hold the eggs in their mouth for protection until the young can swim away.
A grumpy looking fish is the Mangrove toadfish. This species is often mistaken for the distantly related Stonefish. They can vibrate their swim bladder to make a humming or croaking sound, reminiscent of a toad or frog. They ambush fish and shrimps using their camouflage.
Entering the freshwater drains during the wet season, the Sunset or Barred Gudgeon is an aggressive predator. Even aggressive to their own kind it is difficult to keep more than one in an aquarium.
The Lipstick goby is a comical creature found in shallow sandy pools. Males have red pigment on their lips!
This unidentified eel tailed catfish came from the Finniss river estuary.
Siver biddies are cool, they cruise along above the bottom, then plunge their faces into the sand or mud to extract any tasty items buried within. They live in mangrove areas, entering the freshwater after rains.
This Hemigobius is common around Darwin.
Mullet are abundant in mangroves, the Greenback mullet is probably the most commonly seen.
Mangrove Jacks are true snappers found all over the tropical Indo-Pacific. Adults live offshore on deep reefs but the young are common in clean freshwater rivers and creeks.
The Indo Pacific tarpon does not grow anywhere near the size of its Atlantic cousin. It is an air-breather and can be found in almost any freshwater or marine habitat, even the most degraded and polluted.
Named after a friend of mine, Dave Wilson – the Wilson’s mangrove goby is common in the shallow mangrove pools around Darwin.
During the wet season, the Sinuous gudgeon invades freshwater drains to feed on drowned earthworms. They are a large gudgeon or sleeper, commonly exceeding 40cm.
The above three images show the Spotted Scat, a fish that is at home in either salt or coastal freshwater, feeding on algae and muck, including the poo of other fish (Hence the Latin name)…
And there is the Striped Scat also.
Finally the Vachell’s Glassfish is common in mangroves of Northern Australia, being an important food item for many predators.