Dwarf Indian Mudskipper
Periophthalmus novemradiatus
Mudskippers are unique amphibious fish that can breathe air and “walk” on land. They have remarkable adaptations that allow them to move back and forth between water and land. They inhabit coastal areas in the intertidal zone. They are often studied for their relationship in the evolutionary transition of vertebrates from water to land. The two species displayed at the Aquarium of Pacific are in the group Periophthalmus, which is the most varied and common around the world.
SPECIES IN DETAIL
Dwarf Indian Mudskipper
Periophthalmus novemradiatus
CONSERVATION STATUS: Data deficient
CLIMATE CHANGE: Uncertain
At the Aquarium
Harbor Terrace
Geographic Distribution
Dwarf Indian mudskippers are known to reside in limited coastal areas of Bangladesh and eastern India and in southern Thailand (Larson, 2019).
Habitat
Mudskippers are found in tropical climates, in soft mudflats, mangrove swamps, estuaries, and wetlands. They require humid conditions, shallow waters, and brackish to normal seawater.
Physical Characteristics
Various physical adaptations give these unique fish the ability to live comfortably in both aquatic and terrestrial environments.
Mudskippers have large, close-set, googly eyes mounted on the top of their head. Their vision is adapted for both water and air. Their eyes are the only parts that stick out from the mud while they lie in wait for food. They roll their eyes down into small sacs of water underneath when they blink. The mouth is downwards for feeding on the mud surface. Pectoral fins are set forward and underneath the body. The pectoral and caudal fins (tail) are used to propel themselves on land and in water. Their brown, muddy colored skin blends well with their surroundings. The skin is resistant to disease and retains water, which allows them to stay on land for long periods. In males, the first dorsal fin is brown or black, longer, and slightly more curved than in females. Males can also sport colored spots during mating season. Different mudskipper species are distinguished by their body size and appearance, body color pattern, and the number of rays on each fin.
Mudskippers have several ways of breathing and can even breathe in low oxygen conditions. They must have a humid environment, where they can absorb oxygen through the skin and mucus lining of the mouth and throat. Large gill chambers allow them to hold a bubble of air when they burrow. When on land, the gill chambers close tightly to keep in moisture to supply oxygen. Mudskippers can withstand big and fast changes in saline concentrations with the constantly changing tides. They have developed a high tolerance for ammonia in the environment by changes to the liver.
Size
Mudskippers can grow to 7 to 10 centimeters (4 inches), but their average length is less than 6.4 centimeters (2.6 inches).
Diet
Dwarf Indian mudskippers are predominantly carnivorous. In the wild, their diet includes small crustaceans, worms, insects, diatoms, and algae.
Reproduction
Their courtship occurs on land. Males raise and display their dorsal fins to attract a female. He then digs a deep burrow in the mud for the female to deposit her eggs, fertilizes her eggs, and guards them during the incubation period. Falling tides leave burrows filled with oxygen-poor water, so he carries mouthfuls of air to create a chamber of fresh air for the developing eggs. When the eggs are ready to hatch, he removes the air chamber, which then floods the burrow, and the young go out with the rising tide. The young float with other plankton in the open ocean for about 30 to 50 days, then the survivors return to the intertidal zone to establish territory.
Behavior
Dwarf Indian mudskippers spend extended periods of time on land. They can stay active on land for several minutes for feeding, defense, or digging, even in very hot conditions. They use their strong pectoral fins and tail to “walk”, in a style known as “crutching”. They are able to skip, or jump, as far as 60 centimeters (2 feet) in the air. They build mud walls which are about 1 meter (3 feet) high to define their territories. They dig deep burrows up to 1.5 meters (5 feet) deep. The burrows help them to maintain body temperature and provide a defense for themselves and their eggs.
Adaptation
Longevity
Mudskippers can live approximately five years.
Conservation
No conservation measures are currently in place, but mudskipper habitats are within easy reach of humans. These habitats are subject to the human impacts of habitat damage, destruction, coastal pollution, and overfishing. Mudskippers are often studied as a bioindicator of habitat health. Researchers have called for greater environmental protections which will directly affect mudskipper populations.
Special Notes
Mudskippers are air-breathing fish that can live for extended periods on land!
SPECIES IN DETAIL | Print full entry
Dwarf Indian Mudskipper
Periophthalmus novemradiatus
CONSERVATION STATUS: Data deficient
CLIMATE CHANGE: Uncertain
Harbor Terrace
Dwarf Indian mudskippers are known to reside in limited coastal areas of Bangladesh and eastern India and in southern Thailand (Larson, 2019).
Mudskippers are found in tropical climates, in soft mudflats, mangrove swamps, estuaries, and wetlands. They require humid conditions, shallow waters, and brackish to normal seawater.
Various physical adaptations give these unique fish the ability to live comfortably in both aquatic and terrestrial environments.
Mudskippers have large, close-set, googly eyes mounted on the top of their head. Their vision is adapted for both water and air. Their eyes are the only parts that stick out from the mud while they lie in wait for food. They roll their eyes down into small sacs of water underneath when they blink. The mouth is downwards for feeding on the mud surface. Pectoral fins are set forward and underneath the body. The pectoral and caudal fins (tail) are used to propel themselves on land and in water. Their brown, muddy colored skin blends well with their surroundings. The skin is resistant to disease and retains water, which allows them to stay on land for long periods. In males, the first dorsal fin is brown or black, longer, and slightly more curved than in females. Males can also sport colored spots during mating season. Different mudskipper species are distinguished by their body size and appearance, body color pattern, and the number of rays on each fin.
Mudskippers have several ways of breathing and can even breathe in low oxygen conditions. They must have a humid environment, where they can absorb oxygen through the skin and mucus lining of the mouth and throat. Large gill chambers allow them to hold a bubble of air when they burrow. When on land, the gill chambers close tightly to keep in moisture to supply oxygen. Mudskippers can withstand big and fast changes in saline concentrations with the constantly changing tides. They have developed a high tolerance for ammonia in the environment by changes to the liver.
Mudskippers can grow to 7 to 10 centimeters (4 inches), but their average length is less than 6.4 centimeters (2.6 inches).
Dwarf Indian mudskippers are predominantly carnivorous. In the wild, their diet includes small crustaceans, worms, insects, diatoms, and algae.
Their courtship occurs on land. Males raise and display their dorsal fins to attract a female. He then digs a deep burrow in the mud for the female to deposit her eggs, fertilizes her eggs, and guards them during the incubation period. Falling tides leave burrows filled with oxygen-poor water, so he carries mouthfuls of air to create a chamber of fresh air for the developing eggs. When the eggs are ready to hatch, he removes the air chamber, which then floods the burrow, and the young go out with the rising tide. The young float with other plankton in the open ocean for about 30 to 50 days, then the survivors return to the intertidal zone to establish territory.
Dwarf Indian mudskippers spend extended periods of time on land. They can stay active on land for several minutes for feeding, defense, or digging, even in very hot conditions. They use their strong pectoral fins and tail to “walk”, in a style known as “crutching”. They are able to skip, or jump, as far as 60 centimeters (2 feet) in the air. They build mud walls which are about 1 meter (3 feet) high to define their territories. They dig deep burrows up to 1.5 meters (5 feet) deep. The burrows help them to maintain body temperature and provide a defense for themselves and their eggs.
Mudskippers can live approximately five years.
No conservation measures are currently in place, but mudskipper habitats are within easy reach of humans. These habitats are subject to the human impacts of habitat damage, destruction, coastal pollution, and overfishing. Mudskippers are often studied as a bioindicator of habitat health. Researchers have called for greater environmental protections which will directly affect mudskipper populations.
Mudskippers are air-breathing fish that can live for extended periods on land!