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

Clown triggerfish
Clown triggerfish swimming at Ushaka Sea world
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Tetraodontiformes
Family: Balistidae
Genus: Balistoides
Species:
B. conspicillum
Binomial name
Balistoides conspicillum

This fish belongs to the order Tetraodontiformes, which includes pufferfish. Tetraodontiformes are typically found in temperate seas around the world. Fish that belong to this order usually have small temperate mouths.[2]

The family, Balistidae, which is commonly called triggerfish. Currently there are about 37 Balistidae species. This family of fish are very different than other Tetraodontiformes. Unlike the other Tetraodontiformes, their body shape is compressed, with easy to spot scales. Triggerfish have not comprehensively been reviewed enough to have a complete description of them. [2]

Description

edit
 
Because of its coloration, the clown triggerfish is highly prized as an aquarium fish.

Because of its coloration, the clown triggerfish is highly prized as an aquarium fish.

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.[3] This is considered a large fish. 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 clown triggerfish is closely related to two other species: the black triggerfish (Melichthys) and the pineapple triggerfish (Pseudobalistes Flavimarginatus).  Due to the large white spots on the ventral side, the clown triggerfish is harder to mistaken for other species.[2]

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.

The coloration of this fish can play tricks on other fish. For example, the white spots on the ventral side of the fish can be confused, by other fish, with the light rays in the water.[4]

The clown triggerfish’s scales are round and weaker than that of other fish. These scales have 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.[4]

Distribution and habitat

edit

The clown triggerfish is widely distributed throughout the tropical and subtropical waters of the Indian Ocean and in the western Pacific Ocean. These fish typically like being around similarly colored areas such as reefs and coral reefs that have steep drop offs nearby. These environments provide suitable habitats for them, including mating and hiding.[4]

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 until 75 m depth. Juveniles are usually staying below 20 m sheltered close to caves or overhangs.

The clown triggerfish has also been documented in the Israeli Red Sea. This was also most likely due to an aquarium release.[6]

Biology

edit

The clown triggerfish have also been known to reproduce slowly even though they are found all around different reefs.[1] These fish create harems after reaching one year of age. Though they are able to live up to 20 years, but reach sexual maturity at about one year.[4]

The female lays her eggs while the male fertilizes them in sandy patches. From here, the parents will defend the nest, for about eight days, until the eggs hatch. Which is when the female starts to care for them. Typically, clown triggerfish spawn in deep water, which is where the young stay until they grow close to 20cm. [4] This is where the steep drop offs near the reefs comes in handy for the clown triggerfish.

The clown triggerfish can be found in many different oceans, however they can be seldom found in their natural habitats.[7] It is unclear if this species is a rare find or if it’s abundant and just not well documented.[4]

This fish has acrocentric chromosomes, which is pretty common amongst many fish species.[8]

Feeding

edit

Balistoides conspicillum has a varied diet based on different benthic organisms like molluscs, echinoderms and crustaceans.[9] The clown triggerfish has powerful jaws that are typically used during aggressive actions with smaller fish. Due to their strength, this fish is capable of crushing sea urchins and other crustaceans.[4] They have also been seen attacking and consuming crinoids more so than the average reef fish.[10]

Behaviour

edit

This triggerfish has a diurnal activity, is solitary and defends a territory. It can be hard to find this fish in its habitat. It can be very aggressive with other fish and congeners.The clown triggerfish can be sociable the younger it is, however as it gets older, the less sociable and more aggressive it becomes.[3] The first long dorsal spine when is erected, it is used to impress an opponent or to avoid a predator to pull it out of its refuge.

The clown triggerfish does not enter, or rarely enter other triggerfish’s territories. These fish have also not shown aggression towards other triggerfish, only other species of fish.[11]

When the clown triggerfish is in danger it hides in holes. It is capable of locking the spine on their dorsal fin in place, while also locking their smaller dorsal and ventral fin in place. This makes it harder for the fish to be pulled out of their hiding hole.

In aquariums

edit

The clown triggerfish is a common fish found in aquariums and public zoos, since their coloration and pattern is very unique. These fish have been recorded as being difficult to handle, as they’re pretty aggressive, but not as difficult as other species can be. [12]

The juvenile clown triggerfish are sought out after more than adults since juveniles are less aggressive towards other fish.[1] The juvenile clown triggerfish are sought out after more than adults since juveniles are less aggressive towards other fish. 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.[3] It will also prey on invertebrates in the aquarium.[13][14] This fish can become tame enough to be hand-fed; however, one should beware of the fish's sharp teeth.[14] They have been known to take out chunks of flesh while being hand-fed. [3]

Decor in their tanks must be tough, as clown triggerfish will attack them.[3]

Due to the high demand of the clown triggerfish, people tend to capture them in the wild. This can lead to local populations being impacted.[1]

The clown triggerfish, or any triggerfish should not be one of the first fish added to an aquarium. They should be one of the last ones, if not the last fish added as they will most likely not see their tank mates as potential food sources. Any fish or crustaceans added after the triggerfish is added is seen as food and usually attacked quickly.[3]

Conservation Status

edit

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 Israeli 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 a lot of stress. One of the bigger concerns is that the clown triggerfish that have been released into the wild may contain harmful bacteria. Aquarium fish that were from farms often contain harmful bacteria that can decimate aquariums if not treated quickly and properly. For wild fish, coming into contact with farmed fish can be devastating as wild fish would not have any barriers against the harmful bacteria.[6]

Since the clown triggerfish is a highly sought after aquarium fish, being taken straight from the reefs causes problems. Reefs contain coral which are highly sensitive animals. Divers will disturb and destroy  the reefs upon capturing a clown triggerfish which can have devastating consequences on the reefs in those areas, especially towards other reef fish. The clown triggerfish relies on coral reefs for food and shelter, but with the decline in coral reefs, there may be a possibility of a decline in clown triggerfish population in the future.[1]

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 is likely that the introduced fish have not survived, however certain reefs have enough plasticity to include the clown triggerfish.[7][15]

References

edit
  1. ^ a b c d e Matsuura, K. 2022 (2022). "Balistoides conspicillum". IUCN Red List of Threatened Species. 2022: e.T193740A2269848. doi:10.2305/IUCN.UK.2022-2.RLTS.T193740A2269848.en. Retrieved 9 December 2022.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  2. ^ a b c 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. Bibcode:2015IchtR..62...72M. doi:10.1007/s10228-014-0444-5.
  3. ^ a b c d e f Clipperton, John (2013). "Triggerfishes of the Balistidae". UltraMarine Magazine. No. 42. pp. 70–75. ProQuest 1474179877.
  4. ^ a b c d e f g "Clown triggerfish". Toronto Zoo. Retrieved 2024-11-14.
  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. ^ a b 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. Bibcode:2018MarBd..48.1615S. doi:10.1007/s12526-016-0600-4.
  7. ^ a b 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. Bibcode:2017MarBd..47..599M. doi:10.1007/s12526-016-0573-3.
  8. ^ Takai, A; Ojima, Y (1988). "Karyotype and banding analyses in a balisted fish, Balistoides viridescens 'gomamongara'". Chromosome Information Service. 45: 25–27. NAID 10004140755 ProQuest 15965891.
  9. ^ "Clown Triggerfish". The Encyclopedia of Life.
  10. ^ 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. JSTOR 20445573. ProQuest 229308061.
  11. ^ Ziadi-Künzli, Fabienne; Tachihara, Katsunori (February 2016). "Female defence polygyny and plasticity in the mating system of the demersal triggerfish Rhinecanthus aculeatus (Pisces: Balistidae) from Okinawa Island". Marine Biology. 163 (2): 27. Bibcode:2016MarBi.163...27Z. doi:10.1007/s00227-015-2780-z.
  12. ^ Warwick, Clifford; Pilny, Anthony; Steedman, Catrina; Howell, Tiffani; Martínez-Silvestre, Albert; Cadenas, Vanessa; Grant, Rachel (January 2023). "Mobile Zoos and Other Itinerant Animal Handling Events: Current Status and Recommendations for Future Policies". Animals. 13 (2): 214. doi:10.3390/ani13020214. ISSN 2076-2615. PMC 9854913. PMID 36670754.
  13. ^ Dakin, Nick (1992). The Macmillan book of the Marine Aquarium. New York: Macmillan Publishing Company. pp. 177. ISBN 0-02-897108-6.
  14. ^ a b Sanford, Gina (1999). Aquarium Owner's Guide. New York: DK Publishing. pp. 132. ISBN 0-7894-4614-6.
  15. ^ Kemp, J. (September 1998). "Zoogeography of the coral reef fishes of the Socotra Archipelago". Journal of Biogeography. 25 (5): 919–933. Bibcode:1998JBiog..25..919K. doi:10.1046/j.1365-2699.1998.00249.x.
edit