Clown fish

Introduction

Clownfish, also called anemonefish are one of the most popular groups of fish available in the marine fish keeping hobby.  Their delightful character, brilliant colours and hardiness make clownfish wonderful additions to almost any aquarium.
Clownfish belong to the subfamily called Amphiprioninae from the family Pomacentridae which also includes fish commonly referred to as Damsels and Chromis.  There are 28 different species of clownfish, 27 of which belong to the genus Amphiprion and one of the genus Premnas.  These delightful fish are also referred to as anemone fish because of their unique and fascinating relationship with the giant anemones.

Genra	Species	Host Anemone
Amphiprion	akallopisos (skunk)	Entacmaea quadricolor Heteractis magnifica Stichodactyla mertensii
	akindynos (Barrier reef)	Entacmaea quadricolor Heteractis aurora Heteractis crispa Heteractis magnifica Stichodactyla haddoni Stichodactyla mertensii
	allardi (allard's)	Entacmaea quadricolor Heteractis aurora Stichodactyla mertensii
	bicinctus (two-banded/red sea)	Entacmaea quadricolor Heteractis aurora Heteractis crispa Heteractis magnifica Stichodactyla gigantea
	chagosensis (Chagos Islands)	unknown
	chrysogaster (Mauritian)	Heteractis aurora Heteractis magnifica Macrodactyla doreensis Stichodactyla haddoni Stichodactyla mertensii
	chrysopterus (Orange-finned)	Entacmaea quadricolor Heteractis aurora Heteractis crispa Heteractis magnifica Stichodactyla haddoni Stichodactyla mertensii
	clarkii (clarkii)	Cryptodendrum adhaesivum Entacmaea quadricolor Heteractis aurora Heteractis crispa Heteractis magnifica Heteractis malu Macrodactyla doreensis Stichodactyla gigantea Stichodactyla haddoni Stichodactyla mertensii
	ephippium (red saddleback)	Entacmaea quadricolor Heteractis crispa
	frenatus (tomato)	Entacmaea quadicolor Macrodactyla doreensis
	fuscocaudatus (Seychelles Island)	Stichodactyla mertensii
	latezonatus (broadband)	Heteractis crispa
	latifasciatus (Madagascar)	Stichodactyla mertensii
	leucokranos (White bonnet)	Heteractis crispa Heteractis magnifica Stichodactyla mertensii
	mccullochi (McCulloch's)	Entacmaea quadicolor Heteractis crispa
	melanopus (cinnamon/fire)	Entacmaea quadicolor Heteractis crispa Heteractis magnifica
	nigripes (Maldives)	Heteractis magnifica
	ocellaris (false percula)	Entacmaea quadicolor Heteractis magnifica Stichodactyla gigantea Stichodactyla haddoni Stichodactyla mertensii
	omanensis (oman)	Entacmaea quadicolor Heteractis crispa
	percula	Heteractis crispa Heteractis magnifica Stichodactyla gigantea
	perideraion (false skunk/pink)	Heteractis crispa Heteractis magnifica Macrodactyla doreensis Stichodactyla gigantea
	polymnus (brown saddleback)	Heteractis crispa Stichodactyla haddoni
	rubrocinctus (Australian)	Entacmaea quadricolor Stichodactyla gigantea
	sandaracinos (orange skunk)	Heteractis crispa Stichodactyla mertensii
	sebae	Stichodactyla haddoni Stichodactyla mertensii
	thiellei	unknown
	tricinctus (three-band)	Entacmaea quadicolor Heteractis aurora Heteractis crispa Stichodactyla mertensii
Premnas	biaculeatus (maroon)	Entacmaea quadricolor

 
Clownfish are found in abundance only throughout the indo-pacific region of the world, none are found in the Atlantic.  Some species are limited to very small regions of the world and can not be found anywhere else. Some clownfish are very selective when it comes to choosing their host anemones, others are relatively unfussy when it comes to the different anemones that will host clownfish, thereby allowing these species to have a wider natural habitat range then their fussier relatives. 
Although they can be kept quite happily in an aquarium without their host anemone, in the wild they are never found without an anemone.  Most clownfish are very poor swimmers and don't wonder more then a couple feet from their host.  If a clownfish is taken from it's anemone in a wild environment it will quickly be prayed upon by other reef fish.  However anemones can survive quite well with or without a clownfish within it's tentacles.
During the course of evolution clownfish have developed a unique ability to mask themselves from the anemones in which they live.  At one point in time it was thought that clownfish didn't get stung by the anemones due to a think slimy coating. However now it is believed that as the clownfish play in and rub against the anemone's tentacles they pick up small amounts of the anemones cells and effectively becomes invisible to the anemone.  Occasionally the clownfish do get stung if their slime coating is compromised in any way.   

Housing:

Clownfish, being dependant on their host anemones, naturally have a small territory range in which they live so they are ideal candidates for living in relatively smaller aquariums.  A three foot long tank is more then adequate for a pair of clownfish and even smaller nano tanks would be suitable for the smaller members of the clownfish family such as the A. percula and A. ocellaris clownfish.  Clownfish are generally considered reef friendly fish, getting along peacefully with corals, and inverts.   
Even though Clownfish are generally reef safe, some clownfish have such strong bonding instincts in a captive environment (especially with wild caught specimens) they may attempt to bond with anemones or corals with they wouldn't normally associate with in the wild.  Caution should be used when a clownfish attempts to bond with non-traditional inverts because the clownfish could inadvertently stress and damage the invert and even cause the death of the defenseless animals.  The clownfish may need to be removed from the environment if they get to rough with other inverts in a reef tank.  It is not required to have an anemone in the tank with the clownfish, many species will even breed in a tank without a host anemone around. 
As stated earlier, clownfish are closely related to the damsels which are considered aggressive fish.  Although the clownfish are generally less aggressive then other members of the damsel family they can still become very territorial, especially when housed with an anemone.  A. clarkii, A. frenatus, A. melanopus and P. biaculeatus are among the most aggressive of all the clownfish commonly available for sale and should be introduced into the tank after all the less aggressive fish have been firmly established.

Feeding

Clownfish are opportunistic feeders and will readily accept any foods offered to them in a tank.  They will accept fresh, frozen, flake, and freeze dried foods.  A good variety of meaty and vegetative foods should be fed to them.  Ideally they should be fed small amounts of food a couple times a day.  

Disease

Clownfish are susceptible to a number of different diseases such as Marine Ick, Amyloodinium (marine velvet), Brooklynella (clownfish disease) and Head and lateral line erosion (HLLE).  These diseases are more commonly found on wild caught specimens then on tank raised specimens and care should be taken before they are introduced to a fully stocked tank.  When choosing any clownfish for your tank carefully examine them for any signs of disease.  These fish are ideal candidates for quarantine.   

Breeding

Clownfish are one of the easiest marine fish to breed in captivity.  All clownfish are born as non functional males. As they grow, the largest most aggressive fish will change sex and become the female.  The second most dominant fish will become the breeding male and bond with the female.
Once you have a bonded pair, it's best to have them in a separate tank without any other fish.  The tank doesn't need to be large, a 20 to 30Gal tank will be big enough.  When they are comfortable in their environment, they will mate and lay their eggs on a smooth surface.  The male will tend to the eggs, gently fanning them and removing the unfertilized eggs.  The fry will hatch at night in complete darkness after about 8 days.  The fry will need to be fed often on Rotifers for the first 10 to 15days then can be slowly introduced to newly hatched Brineshrimp.  After about 10 to 15 days the fry will also start to take on some colouration and look more like their adult forms.