''Rhinopias frondosa'', the weedy scorpionfish or the weed fish, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Scorpaenidae The Scorpaenidae (also known as scorpionfish) are a family (biology), family of mostly ocean, marine fish that includes many of the world's most venomous species. As their name suggests, scorpionfish have a type of "sting" in the form of sharp ...

, the scorpionfishes. This species is found in the Indo-West

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

. It is a rare but highly desirable fish in the aquarium trade.

Taxonomy

''Rhinopias frondosa'' was first formally described in 1892 by the German-born British

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Albert Günther Albert Karl Ludwig Gotthilf Günther , also Albert Charles Lewis Gotthilf Günther (3October 18301February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile tax ...

with the type locality given as Mauritius. When

Theodore Gill Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist, and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural hist ...

described the new

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Rhinopias ''Rhinopias'' is a genus of marine Actinopterygii, ray-finned fish belonging to the Family (biology), family Scorpaenidae, the scorpionfishes. The species in this genus are found in the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Tax ...

'' in 1905 he designated this species as its

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. This species has been seen associating with '' R. eschmeyeri'' in pairs and it has been suggested that these are the different sexes in a

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

single species. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''frondosa'' means "branched or full of leaves", an allusion to the fleshy tentacles which cover most of the body of this fish.

Description

''Rhinopias frondosa'' has a highly compressed body which is covered in weed like tentacles. It has 12 spines and 9 soft rays in its

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

and 3 spines and 5 soft rays in its

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

. The soft-rayed part of the dorsal fin has two small black spots that have a diameter smaller than that of the orbit. There are fleshy tentacles on the supraocular and posterior lacrimal spines. The distal margins of the soft-rayed parts of the dorsal,

pelvic The pelvis (: pelves or pelvises) is the lower part of an anatomical trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis or pelvic skeleton). ...

, anal and

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

s have either no notches or they are rather weakly notched. The tip of each fin ray in the

is divided into four branches. The spines of the dorsal fin are relatively flexible and have tips which bend easily under even the slightest pressure. The lateral surface of the lacrimal bone is typically smooth or has a bump and the suborbital ridge normally has 3 bumps. There are between 9 and 24 tentacles on the lower jaw, there are tentacles below the eyes and the flanks are covered in tentacles. The fin membranes on the spiny part of the dorsal fin have clear incisions. The colour of this species is very variable but they all have distinctive markings of numerous distinct circular dark-margined spots with the spot in the middle being the same colour as the background colour. This species attains a maximum known

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of .

Distribution

The weedy scorpionfish lives in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

and Western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, from

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and from

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

to the

Caroline Islands The Caroline Islands (or the Carolines) are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically, they are divided between the Federated States of Micronesia (FSM) in the cen ...

. They are found in depths ranging from 13 to 90 meters.

Feeding and behaviour

Like most

, weedy scorpionfish are mostly nocturnal ambush hunters, using their

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

to prey on unsuspecting fish and

invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...

. They rarely swim, but rather move along the bottom propelling themselves with their fins.

In aquarium

The weedy scorpionfish has no commercial value for fisheries, but commands a high price in the

aquarium trade Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. It is a practice that encompasses the art of maintaining one's own aquatic ecosystem, featuring a lot of variety with various ...

. Although they can be found in Eastern waters, they are mostly exported to the west where they fetch a high price due to the difficulty of identifying them in the wild and their issues with contracting diseases from live feeder options as it is extremely difficult to wean them onto prepared food. ''Rhinopias'' are highly sought after by aquarists who collect rare and unusual species. Newly introduced specimen have also been known to change colors if a group of rhinopias are already present in a different color.

References

External links

* {{Taxonbar, from=Q2172282 frondosa Venomous fish Taxa named by Albert Günther Fish described in 1892