Japanese Bullhead Shark (Heterodontus japonicus)

The Japanese Bullhead Shark or Heterodontus japonicus is species of shark from the Heterodontidae family. This saltwater fish is found in the northwestern Pacific Ocean off the coasts of Japan, Korea, and China. They can grow to about 3.9 feet (1.2 meters) in length, and are found on the bottom of the ocean floor in depths of up to 120 feet (37 meters). These sharks can be identified by their short, blunt head and two high dorsal fins each with its own sharp spine for protection. They also have a pattern of irregularly shaped, vertical brown bands and stripes that adorn their bodies.

Japanese Bullhead Shark are known by several names including simply a Bull Head or Cat Shark, but also the Japanese Horn Shark, Cestracion Shark, and Port Jackson shark. These sharks are rather docile and feed on shelled invertebrates and small fish. With molar-like teeth, they grind their crunchy meals to a pulp making them easy to digest. When they reproduce the females will sometimes create communal nests in which they deposit their eggs. Often these nests are located in rock beds or among kelp. These nests are not guarded and the eggs do not hatch for an entire year!  This shark is not considered to be dangerous to humans, but you should be aware of their sharp spines on each dorsal fin.  You can check out the Japanese Bullhead Shark underwater in the video below.


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Port Jackson Shark (Heterodontus portusjacksoni)

The Port Jackson Shark or Heterodontus portusjacksoni is easily confused with its close relative the Horn Shark. In fact, Port Jackson Sharks are something even known as Horn Sharks, and sometimes Bullheads. This type of shark was first discovered in Australia in shallow coastal areas. They have a green coloration with dark markings that cover their bodies in unusual patterns. As you can see in the picture below, they have very strange mouths as well!Port Jackson Sharks can be kept in an aquarium by an expert, but watch out, they have a spine in the front of both dorsal fins that is very sharp and can easily cause injury. An aquarium of at least 1000 gallons is recommended, because these sharks can grow to about 5' in maximum length. The following water conditions in this massive tank are acceptable, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025 and 57-70° F. Although the Port Jackson Shark is hard to keep in an aquarium, once establish they will prove to be quite hardy. In the wild this shark will often feed at night and will eat unsuspecting sleepy fish! In an aquarium you should feed them feeder shrimp, scallops and pieces of marine fish. One more thing to note about the Port Jackson Shark is that you will have to have an aquarium with sand substrate on the bottom, because this fish can easily be damaged by sharper options. This can lead to infection which is never good. You can check out the Port Jackson Shark in action in the video below...

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