A trout cod, or Maccullochella macquariensis, is a large predatory freshwater fish that is indigenous to the waterways of Australia. It is also known as the bluenose cod. The fish is an endangered species, which means that its numbers have declined to such an extent that it is in danger of being extinct in the wild. It is a close relative to the Murray cod, which is a larger, predatory freshwater fish that is known for its ability to adapt to different environments. While the trout cod had been described in various descriptions of fish, it was not until 1972 that it was recognized as a separate species from the Murray cod.
The trout cod is usually bluish-gray in color, but it can also be found in shades of light to dark brown. It is a large fish, with an elongated body and depressed head. Its eyes are small, but they are larger than those of the Murray cod. The fins range in color from light to dark gray. The dorsal fin, or the fin on the back of a fish, is spiny. The largest recorded trout cod was at 31.5 in (80 cm), but it is believed that the fish can grow even larger.
These fish like to live in fast-moving water, but do so under some form of cover, like in rocks or another hiding place. Smaller fish tend to live around rocks, whereas the larger trout cod prefer to dwell in holes or deep pits. The fish are highly territorial and will defend their areas from even their own species.
As carnivores, these creatures eat smaller fish as well as any insects, aquatic or terrestrial, that they can find. The fish will leap to the water’s surface in an attempt to catch anything they feel they may be edible. They may also eat crustaceans, like crayfish and freshwater shrimp. Trout cod tend to be aggressive feeders, especially in lower temperatures.
When the fish are three to five years old, they reach sexual maturity. Adult fish spawn in late spring or early summer, depending on when the water reaches temperatures ranging from 62.6° to 64.4°F (17° to 18°C). Their eggs are adhesive and are usually laid along the bottom of the river or close to it.
In 1988, the fish was added to the Australian Flora and Fauna Guarantee Act. This states that fisherman cannot possess, trade, or catch the fish without a legal permit. Formerly widespread throughout Australia, the only known population is in now the Murray River. Fishing for most trout cod is generally prohibited. In fact, if this species is caught while a fisherman is attempting to catch a Murray Cod, it is recommended that the fish be released with as little damage to it as possible.