Saltwater Aquaristics

The bluestreak cleaner wrasse (Labroides dimidiatus) is one of several species of cleaner wrasses found on coral reefs from Eastern Africa and the Red Sea to French Polynesia. Like other cleaner wrasses, it eats parasites and dead tissue off larger fishes' skin in a mutualistic relationship that provides food and protection for the wrasse, and considerable health benefits for the other fishes. It is also notable for having potentially passed the mirror test, though this is not without controversy. Taxonomy A genetic analysis of L. dimidiatus revealed the population fell into two monophyletic clades, with Indian Ocean populations generally having different stripe widths to western Pacific fishes. The Japanese cleaner wrasses, though, fell within the same group as Indian Ocean fish, despite differing in appearance, and both clades overlap around Papua New Guinea.Two closely related cleaner wrasse species, Labroides pectoralis and Labroides bicolor, were grouped inside the L. dimidiatus clade, so the bluestreak cleaner wrasse may in fact be polyphyletic, incorporating several species. Description  This is a small wrasse, averaging 10 cm (3.9 in) long, at most 14 cm (5.5 in). It can be recognized thanks to a wide longitudinal black stripe running along the side and eye; the back and the stomach are white (sometimes slightly yellowish). This white part changes to a bright blue on the front of the animal, while the black band widens at the tail. The young are black with an electric blue line. Distribution The bluestreak cleaner wrasse is found on coral reefs in the tropics from the Red Sea and Indian Ocean to the western Pacific (including Papua New Guinea, Japan, Fiji, and French Polynesia).[5] It was first recorded from the Kermadec Islands Marine Reserve north of New Zealand in 2015, after researchers examined hundreds of hours of unused documentary film footage. Cleaning Cleaner wrasses are usually found at cleaning stations. Cleaning stations are occupied by different units of cleaner wrasses, such as a group of youths, a pair of adults, or a group of females accompanied by a dominant male. When visitors come near the cleaning stations, the cleaner wrasses greet the visitors by performing a dance-like motion in which they move their rear up and down.The visitors are referred to as "clients". Bluestreak cleaner wrasses clean to consume ectoparasites on client fish for food. The bigger fish recognise them as cleaner fish because they have a lateral stripe along the length of their bodies, and by their movement patterns. Cleaner wrasses greet visitors in an effort to secure the food source and cleaning opportunity with the client. Upon recognising the cleaner and successfully soliciting its attention, the client fish adopts a species-specific pose to allow the cleaner access to its body surface, gills and sometimes mouth.[citation needed] Other fish that engage in such cleaning behavior include goby fish (Elacatinus spp.) The bluestreak cleaner wrasse is known to clean balaenopteridae, chondrichthyans, homaridae, octopodidae, and dermochelyidae In different regions, the bluestreak cleaner wrasse displays various degrees of dependency on clients' ectoparasites as a primary food source. In tidal environments such as the Great Barrier Reef, the bluestreak cleaner wrasse is a facultative cleaner that feeds more on corals than on fish clientele.Juvenile bluestreak cleaners are seen to bite their clients more often than the adults within that region, thus changing the dynamic of the known mutualistic relationship.However, in regions where the bluestreak cleaners are solely dependent on clients' parasites, fish who have access to cleaning services have better body condition than those without cleaner access. In the Marsa Bareika of the Ras Mohamed Nature Reserve, Egypt, the bluestreak cleaner wrasse live in specific sectors of the shallow reefs and are shown to rely on ectoparasites from species such as the brown surgeonfish and white belly damselfish. In this region, fish that visit cleaner wrasses have lower antibody responses than those without cleaner access, suggesting that cleaner access may decrease the need for active immunity. Reproduction Cleaner wrasse males defend specific living territories from other males in which they are able to have control over the females in those territories. When the dominant male no longer exists in that territory, one of the larger females is able to change sexes to take control over that territory.

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Halichoeres chrysus, commonly called the canary wrasse, golden wrasse or yellow wrasse, is a fish species in the wrasse family native to central Indo-Pacific area. Description The canary wrasse is a small fish that can reach a maximum length of 12 cm. It has a thin, elongate body with a terminal mouth. Body coloration is bright yellow with a few variations according to age. Juvenile and immature female have two black spots rimmed with white or light yellow on the dorsal fin (the first one at the start of the fin (head side) and the second in the middle of its dorsal fin) and a third one between the caudal peduncle and the start of the caudal fin. Mature females or young males only show the two black spots on the dorsal fin. Mature males display only the first black spot on the front of the dorsal fin, a lighter-colored spot just behind the eye and irregular greenish to pinkish lines on the face. Distribution and habitat The canary wrasse is widespread throughout the tropical and subtropical waters of the central Indo-Pacific, in an area bordered by the Christmas Islands and Indonesia, Japan, New South Wales and the Rowley Shoals, and the Tonga Islands  and Solomon Islands. This wrasse occurs on outside reef slopes, in rubble and sandy areas from surface down to a depth of 30 meters. Biology The canary wrasse lives in small groups. It is a benthic predator that feeds mainly on small marine invertebrates such as crustaceans, molluscs, worms and echinoderms captured on or in the substrate. Like most wrasse, the canary wrasse is a protogynous hermaphrodite, i.e. individuals start life as females with the capability of turning male later on.

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Lysmata amboinensis is an omnivorous shrimp species known by several common names including the Pacific cleaner shrimp. It is considered a cleaner shrimp as eating parasites and dead tissue from fish makes up a large part of its diet. The species is a natural part of the coral reef ecosystem and is widespread across the tropics typically living at depths of 5–40 metres (16–131 ft). Lysmata amboinensis can reach a body length of 5–6 centimetres (2.0–2.4 in) and have long white antennae. Mature shrimp are pale in colour with longitudinal bands on their carapace; one central white band with wider scarlet red bands on either side. The shrimp has a long larval stage and unusual sexual maturation, initially being male but becoming a functional hermaphrodite once mature. Lysmata amboinensis is popular in home and public aquaria where it is commonly referred to as the skunk cleaner shrimp; this is due to its striking colours, peaceful nature, and useful symbiotic cleaning relationship which can also be witnessed in captivity. Adult shrimp can reach a body length of 5–6 centimetres (2.0–2.4 in) with two pairs of long white antennae. The body and legs are pale amber in colour with longitudinal bands on the carapace: one central white band is flanked by wider scarlet red bands. There are several symmetrical white spots on the red tail. The most anterior antennae fork into two making the shrimp appear to have three pairs of antennae. As with all decapods there are 10 pairs of walking legs, with the most anterior pair having forceps (pincers). Anterior to the walking legs are a pair of white maxillipeds used for feeding. Underneath the thorax behind the walking legs are paired pleopods (swimmerets) used for swimming and brooding eggs.[Lysmata amboinesis have a pair of stalked eyes though experiments suggest they have coarse vision and are colour blind; this low spatial resolution makes it unlikely they can see the striking patterns of other shrimps or tropical fish. Distribution and habita Lysmata amboinensis is native to coral reefs across the tropics including the Red Sea and the Indo-Pacific Ocean. They live on tropical coral reefs between depths of 5–40 metres (16–131 ft) and are typically found in caves or reef ledges. Life cycle Lysmata amboinesis lay eggs which the adult shrimp keep attached to their pleopods. The early larvae are called nauplii which hatch into more developed larvae called zoeae and go through a free-floating planktonic stage. During this time they feed on other plankton and moult through 14 identified stages growing to approximately 2 centimetres (0.79 in) in length over 5–6 months. At this point the larvae will settle and metamorphose into a more mature form, though not yet the adult state. This is achieved after several moults which occur every 3–8 weeks. Each shrimp starts out as a male, but after a few moults will become a hermaphrodite allowing them to function as both male and female in interactions with another shrimp; these shrimp have no pure female form. This form of sexual maturation is scientifically described as 'protandric simultaneous hermaphroditism' and is unique to Lysmata shrimp amongst other decapod crustaceans. In one spawning, adult shrimp will lay between 200–500 eggs which are initially attached to the pleopods and are greenish in colour; the eggs swell and lighten in colour before hatching and a few will turn silver on the day of hatching. The eggs hatch around dusk releasing 3–4 millimetres (0.12–0.16 in) long larvae into the free-floating pelagic zone. Behaviour Lysmata amboinesis do not live in large groups, more often in pairs, and while omnivorous it is believed they derive much of their nutrition from cleaning parasites and dead tissue from fish. Their mating behaviour has been observed in captivity where it involves little ritual: a pair of fully mature hermaphroditic shrimp will alternate moulting timing, mating occurs shortly following a moult when one shrimp acting as the male will follow the other acting as the female which will brood the fertilised eggs; when the next shrimp moults the roles, and therefore apparent sex, will reverse. In captivity L. amboinesis have been seen to be socially monogamous showing such aggression that if they are kept in groups of more than 2 individuals one pair will kill the rest. While they are not generally seen in large groups in the wild it is unknown if they are socially monogamous in their natural environment. Symbiosis Lysmata amboinesis, like other cleaner shrimp, has a symbiotic relationship with 'client' fish in which both organisms benefit; the shrimp gain a meal from eating parasites living on large fish and the clients benefit from the removal of parasites. Cleaning organisms including shrimp and fish can congregate in one location on a reef in what is called a "cleaning station" which fish will visit when required; cleaning shrimp perform a rocking dance from side to side to signal their services when fish approach. Removal of parasites under captive conditions happens mainly at night though it is unknown whether this is due to shrimp or host fish behaviour.Additionally, cleaning services provided by the shrimp aid wound healing of injured fish supporting the symbiosis hypothesis. L. amboinesis is also commonly found living in caves with their client fish, such as moray eels, providing the shrimp with protection from predators. Because of the benefits of cleaner shrimp to the fish they clean, Lysmata amboinensis and other species have been suggested as potentially useful to aquaculture. Common name Lysmata amboinesis within the marine aquarium trade is commonly referred to as the skunk cleaner shrimp, white-banded cleaner shrimp or scarlet cleaner shrimp due to its appearance, however this last name is also sometimes used for Lysmata debelius. In the aquarium Many species of Lysmata, including L. amboinesis, are commonly kept in salt water aquaria; they are safe and beneficial since they will clean both the tank and fish but not harm corals. For these reasons they are often kept in both home and public aquaria for educational purposes, sometimes in 'touch pools' which allow visitors to put their hand in the water so the shrimp will clean their hand. Despite significant efforts L. amboinesis remains difficult to culture in captivity, though adults will regularly spawn eggs. The cycle from spawning to adult form takes approximately 6 months during which time the vast majority of larvae die. As such most shrimps sold in the aquarium industry are wild-caught, this has led to concern about the negative effects of their removal on natural reefs though there is currently no evidence of an effect.

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