Cirrhitichthys aprinus – Spotted Hawkfish

Cirrhitichthys aprinus – Spotted Hawkfish

Cirrhitichthys aprinus was first described by French zoologist Georges Cuvier in 1829. This fish belongs to the family Cirrhitidae, which is known as the Hawkfish. The family Cirrhitidae consists of 12 genera and about 33 species. Their common name is Spotted Hawkfish.

The genus name Cirrhitichthys is derived from the Latin “cirrus” meaning “curl” or “fringe” and the Greek “ichthys” meaning “fish”. The species name aprinus means “bear-like” (as in a male pig), a reference to the large canine teeth on the sides of the lower jaw.

Synonyms: Cirrhites aprinus, Cirrhitichthys analis, Cirrhitichthys graphidopterus.

Description

General description:
The Spotted Coral Climber has an elongated body with a standard length of about two and a half times the depth of the body. The base color of the body is whitish with broad, dark reddish-brown vertical stripes on the sides. These stripes are interrupted by light stripes with diamond-shaped dark spots where they cross the lateral line. The head and body are covered with cycloid scales and the preoperculum is strongly serrated. The fins are translucent and unmarked, except for the dorsal fin which has white filaments at the tips of the spines. The maximum length of this species is 12.5 centimeters.

Differences between males and females:
There are no obvious physical differences between males and females. However, both sexes can change sex, with a female becoming a male if necessary.

Behavior and Temperament:
The Spotted Hawkfish is a solitary fish that often sits on rocks or corals and observes its surroundings. They are generally aggressive towards other hawkfish, especially if there are not enough hiding places. However, they can live well with other fish species, as long as they are not too small and docile. These fish are not shy and can even be hand-fed.

Swim bladder

The Spotted Hawkfish lacks a swim bladder, which is unique among fish. The swim bladder is a gas-filled organ that many fish use to regulate their buoyancy, allowing them to remain at a certain depth without much effort. The lack of a swim bladder in the Spotted Hawkfish has some specific benefits and implications for their behavior and swimming.

Benefits of not having a swim bladder

1. Stability on the bottom : Without a swim bladder, these fish are better able to rest stably on the bottom or on rocks and corals without floating. This is especially useful for their lifestyle, as they often sit on a high spot and observe the surroundings in search of prey.
2. Quick movements : The lack of a swim bladder allows the Spotted Hawkfish to make quick and sudden movements. This is useful for hunting, as they can dive quickly to catch prey without having to adjust their buoyancy first.
3. Reduced risk of barotrauma : Fish with a swim bladder can suffer from barotrauma when changing depth quickly because the pressure in the swim bladder cannot be adjusted quickly enough. Fish without a swim bladder, such as the Spotted Coral Climber, do not have this problem and can change depth quickly without any problems.

Swimming behavior without swim bladder

Without a swim bladder, Spotted Hawkfish must actively control their buoyancy and position in the water using their fins. They use their strong pelvic fins as support points when resting on rocks or corals. These fins are adapted to help them stay stable and hold onto surfaces.

When swimming, they must constantly use their fins to keep moving and maintain their position in the water. This means that they use more energy when swimming compared to fish that have a swim bladder. However, their lifestyle as sedentary predators means that they do not have to swim constantly and can often sit still for long periods of time, which reduces their energy consumption.

Protogynous hermaphrodism

Protogynous hermaphrodism is a fascinating phenomenon that occurs in Cirrhitichthys aprinus. This means that individuals of this species can change sex, specifically from female to male. This process is an adaptive strategy that helps them to maximize their reproductive success in their natural environment.

What is protogynous hermaphrodism?

Protogynous hermaphrodism is a form of sequential hermaphroditism in which a fish starts out as a female and changes to a male later in life. This is common in fish species that live in social groups where reproductive dynamics depend on the presence of dominant males and multiple females.

Benefits of Protogynous Hermaphrodism

1. Optimization of reproductive success : In an environment where males are limited, females that change into males can increase the reproductive chances of the group. This ensures that there is always a male available to mate with the females.
2. Flexibility in social structures : Protogynous hermaphrodism allows the spotted coral guard to respond flexibly to changes in the social structure of their group. If a dominant male dies or disappears, one of the females can quickly take over the male’s role, thus maintaining the stability of the group.
3. Increased genetic diversity : By changing sex, individuals can contribute to the genetic diversity of the population, which is important for the long-term survival and adaptation of the species.

How does it work with the Spotted Hawkfish?

In the Spotted Hawkfish, fish often live in harems, consisting of one dominant male and several females. When the dominant male disappears, for example, due to predation or other causes, one of the largest and strongest females in the group may begin the process of changing sex. This process involves hormonal changes that lead to the development of male secondary sexual characteristics and the production of sperm instead of eggs.

Behavioral changes

In addition to physical changes, behavioral changes can also occur. The new male will often take on a more dominant and territorial role, which is essential for protecting the harem and ensuring reproductive success.

Biotope

Natural Distribution:
The Spotted Coral Climber is found in the tropical waters of the Indo-West Pacific, including the Maldives, the Western Pacific, and the coasts of Australia. They are often found in rocky and coral-rich areas of subtidal coastal reefs, but can also occur in shallow harbors and estuaries.

Natural habitat:
Their natural habitat consists of rocky and coral-rich areas with a depth range of 5 to 40 meters. The bottom usually consists of coral and rocks, which provide sufficient hiding places for this species.

Natural enemies and hunting behavior:
Cirrhitichthys aprinus is a predatory fish that feeds on small fish and crustaceans. There are no specific data on their natural enemies.

Diet

Diet in the wild:
In the wild, the spotted coral guard primarily feeds on small fish and crustaceans.

Diet in the aquarium:
In the aquarium, they can be fed a variety of meaty foods, such as mysis, gammarus, krill, and other crustaceans. They will also accept dry, freeze-dried, or frozen foods.

Feeding advice:
It is advisable not to feed small, weak fish species or small crustaceans such as shrimp and crabs, as these can be seen as prey. They are reef-safe, but can sometimes rest on corals, which some corals do not tolerate well.

The Aquarium

Aquarium Size:
A minimum 150 liter (40-gallon) aquarium is suitable for keeping a single Spotted Coral Climber. Multiple pairs will require a larger aquarium, preferably with plenty of hiding places and rock formations.

Aquarium decoration:
The aquarium should be setup with lots of rocks and corals to provide enough hiding places. A sand or gravel substrate is suitable.

Water Parameters:
Ideal water conditions for this species are a temperature of 22-27°C, a pH of 8.0-8.5, and a specific gravity of 1.020-1.026.

Introduction to the aquarium:
It is best to introduce this species into a well-matured aquarium so that there are sufficient algae and microorganisms present.

Suitable Tankmates:
This species can live well with other moderately aggressive fish such as Clownfish, Surgeonfish, and larger Wrasse. They should not be kept with small, weak fish or small crustaceans.

Breeding Cirrhitichthys aprinus

There are no specific data on breeding Cirrhitichthys aprinus in an aquarium. It is known that they have laid eggs in captivity, but the young have not been raised.

Conclusion

Cirrhitichthys aprinus is an interesting and relatively easy fish to keep for advanced aquarists. They are hardy and adaptable to a variety of conditions, provided there are sufficient hiding places and a varied diet. Their aggressive nature towards conspecifics and small crustaceans makes them unsuitable for mixed tanks with small, docile species. Overall, they are an interesting addition to a well-established reef or community tank.

Video

Author

John de Lange

Copyright images

Doug Anderson
John Turnbull – CC BY-NC-SA 2.0
Francois Libert (Zsispeo) – CC BY-NC-SA 2.0