# Captive Breeding of Clownfish Species for the Aquarist Trade. How Has it Benefitted



## Richcymru (Nov 21, 2008)

*Here is a report by a friend of mine (struvas) on clownfish that I thought people might find interesting:*​
​ Clownfish have been one of the most successful marine fish to have been captured from tropical reefs and captive bred, to be sold in the aquarist trade as ornamental fish. (Avella et al, 2007). There are a large number of different types of the _Amphiprion_ clownfish species, which are found throughout the world in warmer tropical waters around Asia, Africa, Oceania, and America.


Originally, they were captured from reefs using a variety of different methods such as netting, hand collection or by cyanide fishing (Wyllie,1994). These methods of collection were by no means sustainable, especially in the face of ever-increasing demand, accentuated by such films as “Finding Nemo”, which was released in 2002, made the clownfish very desirable to the public market.


From 1997 to 2002, _Amphiprion ocellaris _were the most common marine ornamental fish found in marine aquariums, making up 15.6% of the total number of exported marine fish(Wabnitz et al., 2003). Originally, these were kept without the correct equipment and resulting in high numbers of mortalities so that ever-increasing numbers of fish were being collected from tropical reefs, such as the Great Barrier Reef of Australia. This led to a decline in the wild populations. (Shuman, 2004)


With the increasing demand for live reef fish for home and public aquariums in countries such as the USA, Singapore and the United Kingdom, the ‘traditional’ collection methods became unsustainable and proved fatal, killing not just reef fish, but also invertebrates such as corals and shrimps. There were a number of these methods for catching reef fish such as large nets being placed around areas of the reefs for days on end to catch as many fish as possible, leaving many dead or wounded with damaged gills (Dominguez et al., 2007). Cyanide usage also increased, whereby a team of divers would spray cyanide into small crevices and holes around the reef, stunning the fish and making them easier to catch (Jones et al. 1997). This method meant that fish species could be hand selected, leading to hundreds or even thousands of fish being taken off the reef. The cyanide used was also toxic to the fish species, killing many of the fish which had been caught, or badly damaging them, meaning if any fish were left un-captured they were very vulnerable to predators (Barber, 1998).
Cyanide fishing also had secondary factors as it killed many corals by damaging the symbiotic algae (zooxanthellae) in the coral, reducing its ability to photosynthesise and leading to coral bleaching in many areas of the reef (Jones,1999) .


Fortunately in the last few years, sustainable methods for collecting reef fish have been enforced. Many of the collection areas have also banned the use of cyanide to catch fish. Quotas have also been put on the number of fish which are taken from the reef, and importers have to meet these figures. Catches are also now recorded so that the numbers of fish being caught can be monitored (Holland et al., 1996).


Another major improvement is that resulting from the use of artificial reefs, despite the fact that they are man-made. Decommissioned ships, rubble or purpose-built reef structures are laid down on the seabed and act as artificial hard substrate for corals to inhabit. These then form new habitats, breeding grounds and refuge zones for clownfish and other reef fishes and invertebrates (Stephen et al.,2007). 


Marine Protected Areas (MPA) have also been put in place on many reefs, where quotas have been put in place to prevent over fishing, or complete bans on fishing have been imposed to encourage the re-introduction of fish species, and to build up populations . For example, in the Red Sea, exports of fish species have been completely stopped from the reefs, and populations of reef fish such as _Amphiprion percula_ (Percula Clownfish) have been able to re-establish their populations. Another reef fish called the Humphead wrasse(_Cheilinus undulates_) is now found on the red list of endangered reef fish, due to juvenile fish being overfished for the aquarist trade, and larger fish being exploited for food (Shuman, 2004).


The Marine Aquarium Council (MAC) and Ecosystem and Fisheries Management (EFM) are an international, non profit organisations. They deal with most of the international imports and exports of fish and invertebrates from the main collection reefs around the world such as in the Red Sea and on the Great Barrier Reef in Australia. They work with conservation organisations and government agencies around the world and have helped to conserve many marine ecosystems. 


The organisation also assists and educates many exporting companies into proper fish and invertebrate collection methods including the disuse of cyanide. New high standards have to be met to comply with the ethical trade of marine fish, and correct methods of packaging and transportation are enforced to minimise the stress for the reef fish (Shuman, 2004) MAC also work hand in hand with public aquariums to aid breeding projects of various marine fish species, including the clownfish.


This influence can be seen in a number of public aquariums worldwide including the Blue Planet Aquarium in Ellesmere Port in Chester, where the reef magic exhibition shows a large aquarium containing tank bred clownfish which the public aquarium had bred onsite.


There are many companies worldwide but one of the main one in the Europe is Tropical Marine Centre (TMC), which works with the environmental issues of collection and importation of the marine fish and invertebrates and guarantees all the species of fish they sell are net caught and have suffered minimal stress. 


TMC have recently built on-site hatcheries and provided fish selling businesses in the UK with tank-raised species of fish and invertebrates - fortunately including many species of _Amphiprion_ clownfish as well as Damsel fish, Dottybacks, and _Hippocampus _species (Seahorses).The company also sell invertebrates such as shrimps and corals, of which many are tank-raised, or grown and fragged in specific coral tanks. Many companies are now following examples such as TMC, making fish collection from tropical reefs more sustainable.


Clownfish are, in fact, one of the more relatively easier marine fish to breed in captivity. In the wild, Clownfish use a host tropical anemone with which they establish a symbiotic relationship. They use cellular recognition with each other so that the anenome doesn’t sting the clownfish and is able to use it as a protective home against other fish species that aren’t able to live in symbiosis with anemones. The clownfish keeps the host anenome clean and free of any sand particles or algae to fulfil its side of the deal (Lubbock, 1981). The clownfish will lay its eggs within the tentacles of the anenome and guard them until they hatch into larvae and are dispersed over the reef (Jones et al., 2005) 


The process of breeding is complicated and happens over the duration of a year, where the pair of clownfish will reach sexual maturity. The breeding process is very similar in all of the _Amphiprion_ species of clownfish. Firstly the clownfish will become monogamous pairs and will stay together until one of the pair dies. All clownfish species are protandric hermaphrodites, starting off as all males. They will argue and fight during this immature stage until a dominant female is decided, which in most clownfish species will grow larger than the male.(Allen, 1975)


The fish will then stay as a pair and will become sexually mature. They will then decide on a area suitable for spawning, which will become the pairs territory (Buston, 2004)


The spawning site can range from a coral frag, a prominent rock, a plant pot or a cave and does not have to be an anemone unlike in the wild. This may be due to there being less of a threat in an aquarium from predators, unlike in the open ocean, so the clownfish may not see the need for an anemone host to protect the clutch of eggs. Nevertheless the pair will thoroughly protect the clutch of eggs from any of the other aquarium inhabitants. The Parents will fan the eggs using their pectoral fins cleaning the eggs and providing the eggs with oxygen. The fanning also removes any dead eggs. (Green et al, 2004) 


The clownfish can lay up to 800 eggs in one clutch, which start an orange colour, and slowly turn red as the larvae develop inside the egg. The eggs will then hatch after a 6-8 days into small free swimming pelagic larvae, which will subsist off of their egg sac for a few days and will begin the development of the digestive tract, the pelvic fins and its yellow to orange pigmentation as seen in adult fish. (Yasir et al ,2007)

After the juvenile clownfish have digested the yolk sac they are able to ingest micro plankton and rotifers, which are readily available on the market and very similar to what they would eat in the wild. The larvae will search the food using binocular vision and are able to hunt and eat and prey if it is a body length away, either side of the clownfish larvae. (Coughlin, 1993)


The Development of larvae into juvenile clownfish in _Amphiprion ocellaris_, (Common Clownfish), _Amphiprion percula_, (Percula Clownfish) and _Amphriprion melanopus _(Fire Clownfish) are very similar. Once the larval stage has ended roughly after 8-10 days the larvae will metamorphose into a juvenile fish and will develop the characteristic white bars on its ventral sides, and is able to actively hunt prey such as rotifers and freshly hatched artemia. * (*Arvedlund et al, 2000)
The juvenile fish will then develop over the year into fully mature fish. Survival rates of the larvae will depend on whether the larvae have been eaten by any other fish or corals in the aquarium, or if they have been taken into the filtering system and killed.


New species of clownfish have also produced such as the Black common Clownfish, _Amphiprion ocellaris_, which isn’t found in the wild, but is now regularly found in the trade. Which has been cultured by breeding two darker common Clownfish, and through generation to generation the juvenile fish have become completely black, with the white bars on the fishes ventral side.

Overall the clownfish are one of the easier marine fish to be cultured and nowadays are bred on a commercial scale, meaning that wild populations of clownfish aren’t suffering as much as they were in 2002 and 2003. Thankfully wild populations are increasing and seen more and more on worldwide reefs especially in the Red Sea, the Indian ocean and on the Great Barrier Reef in Australia (Holland et al, 1996). 


One Improvement in cultured clownfish species is that they have become more resistant to aquarium diseases such as marine Ich or any parasites which have come from the oceans. Cultured clownfish will also suffer less stress than wild caught specimens, as they will readily accept the confined spaces of aquaria as they have been brought up in a confined environment unlike wild caught fish which aren’t used to the barriers. (Charles S, 1998)




This has all led to a reduction in the number of clownfish dyeing in aquariums, as well as other tank bred species of fish and invertebrates such as the Neon Goby _Gobiosoma oceanop _which was originally caught in The Western Atlantic around the Gulf of Mexico. Originally it was prone to stress and other marine diseases such as Ich but nowadays it is pretty much white-spot resistant, and readily breeds in aquarium conditions. It is also now rarely caught in the wild, again leading to increased wild populations.


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## Richcymru (Nov 21, 2008)

*Conclusion*

In the last 20 years technology in marine aquariums have improved drastically. The introduction of protein skimmers to remove excess proteins and lipids in the tank are readily used, larger filtering systems are also used to keep aquariums as healthy and as clean as possible and are relatively cheap. Lighting for aquariums have also been improved, making it more natural for the marine fish living in the aquarium, using daylight cycles and night lights to represent the moon, has proven to promote spawning of fish and corals.


All of this technology has led to it being relatively easy to keep marine fish especially in the last 5 years where prices of systems with inbuilt lights filters, skimmers and heaters are very low. 


All of this technology has made it accessible for the normal hobbyist to keep marine fish with ease, and in a minimal stress environment, which represents their natural habitat. This technology has also led to the captive breeding of many types of marine fish such as the _Amphiprion _species of clownfish which is now considered as the ‘goldfish’ of the marine aquarium as it is so readily available with minimal environmental costs thanks to companies such as TMC.(Hoff, 1996)


With reduced numbers of Clownfish being taken from tropical reefs due to the development of captive breeding, as well as many other marine fish species the future of many species of marine fish which were once over fished for aquariums is now looking bright, and will hopefully continue to do so for more and more species of marine fish. 


New species of clownfish are also being produced due to captive breeding programmes such as the Black Common Clownfish _Amphiprion ocellaris_
With benefits such as disease resilience it is making it easier for the everyday hobbyist to keep tropical marine fish, and to be able enjoy their beauty, and natural behaviour which is normally only seen on tropical reefs, in your front room more and more people are starting up their own reef aquarium, instead of the more common tropical freshwater aquarium.































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