Biology:Clown triggerfish

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Short description: Species of fish

Clown triggerfish
At uShaka Marine World
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Tetraodontiformes
Family: Balistidae
Genus: Balistoides
Species:
B. conspicillum
Binomial name
Balistoides conspicillum
(Bloch & J. G. Schneider, 1801)

The clown triggerfish (Balistoides conspicillum), also known as the bigspotted triggerfish, is a demersal marine fish.

Taxonomy

Although it is in the genus Balistoides alongside the titan triggerfish (Balistoides viridescens), the genus is not monophyletic and requires revision. As a result, the clown and titan triggerfish are not each other's closest relatives. The clown triggerfish is possibly most closely related to species of the genus Melichthys and the orange-lined triggerfish (Balistapus undulatus).[2][3]

Description

Juvenile, in South Africa
In the Maldives

The clown triggerfish is a fish which grows up to 50 cm (19.7 inches) in the wild, however, in captivity it does not usually reach that length.[4] Its body has a stocky appearance, oval shape and compressed laterally. The head is large and represents approximately one third of the body length. The mouth is small, terminal and has strong teeth.

The first dorsal fin is composed of three spines, one of which is longer and stronger. It is erectile and hidden in a dorsal furrow. This set of dorsal spines composed a trigger system which is a characteristic from the family Balistidae. The second dorsal fin is similar in shape and size to the anal fin which is symmetrically opposed to it. The pelvic fin is reduced to a ventral protrusion.

The background coloration is black. Half of inferior part of the body is marked with big white spots which are more or less round. The area around the first dorsal fin is crossed by yellowish sinuosities which draw like a network reminding the leopard's patterns. There is a yellowish ring around the mouth, which is surrounded by another fin white ring. A white stripe ride the snout just under the eyes level. The second dorsal fin and the anal fin are white and underlined with a yellow line at their base. The caudal peduncle has a yellowish blotch on its top part and has three horizontal sets of spiny scales. The caudal fin is yellowish in its center and has black margin. Juveniles have a black background coloration spangled with small white spots, the extremity of the snout and the base of the first dorsal fin is yellowish.

These scales are thick, weakly overlapping, with a rhomboid shape. Each scale has two layers: the topmost layer being bone and the lower layer being collagenous.[5]

This fish has teeth that continuously grow. These teeth help them when feeding on crustaceans.[6]

Distribution and habitat

In Indonesia

The clown triggerfish is widely distributed throughout the tropical and subtropical waters of the Indian Ocean and in the western Pacific Ocean.[1]

A single record was reported in the Mediterranean Sea in Spanish waters in 2012, a likely aquarium release. It is most commonly found along external reef slopes with clear water with a depth of 1–75 m. Juveniles usually stay below depths of 20 m, and inhabit caves or overhangs.[1]

The clown triggerfish has also been documented in the Red Sea. This was also most likely due to an aquarium release.[7]

Biology

With fully extended dorsal and pelvic spines, in New Caledonia

Although the clown triggerfish is widely distributed, it occurs in low numbers in the wild. However, this fish can be locally abundant in areas with high biodiversity.[1] These fish create harems after reaching one year of age. Though they are able to live up to 20 years, they reach sexual maturity at about one year.[6]


Feeding

Balistoides conspicillum has a varied diet based on different benthic organisms like molluscs, echinoderms and crustaceans.[8] They have also been recorded feeding on crinoids.[9]

Behaviour

In aquariums

At Yehliu Ocean World
At Two Oceans Aquarium

Because of its attractive coloration, this fish is one of the most highly prized aquarium fish.[10]

The juvenile clown triggerfish are sought out after more than adults since juveniles are less aggressive towards other fish.[1] Like many other triggerfish, it can require a large aquarium and be aggressive towards other fish. It should not be kept with small fish. Clown triggerfish can be housed with other large fish species such as moray eels and angelfish, but they thrive when kept alone.[4] It will also prey on invertebrates in the aquarium.[11][12] This fish can become tame enough to be hand-fed; however, one should beware of the fish's sharp teeth.[12] They have been known to take out chunks of flesh while being hand-fed.[4]


There is high demand of the clown triggerfish in aquariums, and all captive specimens are caught in the wild. This can lead to local populations being impacted.[1]


Conservation status

The clown trigger fish is of least concern, however, this fish has been introduced into different ecosystems in different parts of the world. One place in particular is the Red Sea, in which the clown triggerfish was introduced, most likely intentionally, by a private aquarium keeper. This sea has a fragile ecosystem that has been under considerable stress from human impacts. One of the concerns is that the clown triggerfish that have been released into the wild may contain harmful bacteria that can impact wild fish[7]

Due to the clown triggerfish most likely being introduced by an aquarium, there could be potentially harmful effects, though the effects have not fully been recorded. It has also been recorded occasionally in the Mediterranean. While introduced reef fish species typically do not successfully establish in the Mediterranean, certain reef fish species have enough behavioural plasticity to successful invade non-native Mediterranean habitats.[13][14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Matsuura, K. 2022 (2022). "Balistoides conspicillum". IUCN Red List of Threatened Species 2022. doi:10.2305/IUCN.UK.2022-2.RLTS.T193740A2269848.en. https://www.iucnredlist.org/species/193740/2269848. Retrieved 9 December 2022. 
  2. ↑ Matsuura, Keiichi (January 2015). "Taxonomy and systematics of tetraodontiform fishes: a review focusing primarily on progress in the period from 1980 to 2014". Ichthyological Research 62 (1): 72–113. doi:10.1007/s10228-014-0444-5. Bibcode: 2015IchtR..62...72M. 
  3. ↑ McCord, Charlene L.; Westneat, Mark W. (January 2016). "Phylogenetic relationships and the evolution of BMP4 in triggerfishes and filefishes (Balistoidea)" (in en). Molecular Phylogenetics and Evolution 94 (Pt A): 397–409. doi:10.1016/j.ympev.2015.09.014. PMID 26408967. Bibcode: 2016MolPE..94..397M. 
  4. ↑ 4.0 4.1 4.2 Clipperton, John (2013). "Triggerfishes of the Balistidae". UltraMarine Magazine (42): 70–75. ProQuest 1474179877. 
  5. ↑ Meunier, F J (March 2009). "Structure and mineralization of the scales in the clown trigger-fish Balistoides conspicillum (Teleostei: Tetraodontiformes: Balistidae)". Cahiers de biologie marine 50 (1): 47–56. INIST:21280291 ProQuest 20181111. 
  6. ↑ 6.0 6.1 "Clown triggerfish". https://www.torontozoo.com/animals/Clown%20triggerfish. 
  7. ↑ 7.0 7.1 Stern, Nir; Rachmilovitz, Elad N.; Sharon, Galit; Diamant, Ariel (September 2018). "The dire implications of releasing marine ornamental fishes into the wild: first reported case from the Red Sea". Marine Biodiversity 48 (3): 1615–1620. doi:10.1007/s12526-016-0600-4. Bibcode: 2018MarBd..48.1615S. 
  8. ↑
  9. ↑ Baumiller, Tomasz K.; Mooi, Rich; Messing, Charles G. (2008). "Urchins in the Meadow: Paleobiological and Evolutionary Implications of Cidaroid Predation on Crinoids". Paleobiology 34 (1): 22–34. doi:10.1666/07031.1. ProQuest 229308061. Bibcode: 2008Pbio...34...22B. 
  10. ↑ "Balistoides conspicillum summary page" (in en). https://www.fishbase.se/summary/2300. 
  11. ↑ Dakin, Nick (1992). The Macmillan book of the Marine Aquarium. New York: Macmillan Publishing Company. pp. 177. ISBN 0-02-897108-6. https://archive.org/details/macmillanbookofm0000daki/page/177. 
  12. ↑ 12.0 12.1 Sanford, Gina (1999). Aquarium Owner's Guide. New York: DK Publishing. pp. 132. ISBN 0-7894-4614-6. https://archive.org/details/aquariumownersgu00sand/page/132. 
  13. ↑ Marcelli, Massimiliano; Dayan, Abraham Rami; Langeneck, Joachim (June 2017). "Finding Dory: first record of Paracanthurus hepatus (Perciformes: Acanthuridae) in the Mediterranean Sea". Marine Biodiversity 47 (2): 599–602. doi:10.1007/s12526-016-0573-3. Bibcode: 2017MarBd..47..599M. 
  14. ↑ Kemp, J. (September 1998). "Zoogeography of the coral reef fishes of the Socotra Archipelago". Journal of Biogeography 25 (5): 919–933. doi:10.1046/j.1365-2699.1998.00249.x. Bibcode: 1998JBiog..25..919K. 

Wikidata ☰ Q973548 entry




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