The zooplankton-feeding wrasses are some of the best-suited fish for the home aquarium — especially reef tanks. They will not bother sessile invertebrates (e.g., corals) and tend to spend their time in the water column where they can be viewed and appreciated by their keepers. There are several genera in this feeding guild that are well-represented in the aquarium trade.
Fairy wrasses (Cirrhilabrus spp.). This is one of the largest genera of wrasses. It is comprised of some of the most exquisite fish in the sea. They will consume most aquarium foods and can be kept singly or in groups (one male and two or more females). Males will display to females and rivals by spreading their fins and intensifying their color (referred to as “flashing”). While they are great for the reef tank and can be a sight to behold in the home aquarium, they do have some downsides. They are prone to jumping out of uncovered tanks or even out of holes in the aquarium top; they may also go over the overflow box. In addition, they are not some of the more fascinating wrasses from a behavioral standpoint — they spend most of their time sculling about the aquarium in a bobbing motion. Their brilliant hues may become more subdued in captivity. This may be the result of keeping them under very bright lighting (such as the lighting found over reef aquariums), nutritional deficiencies or the lack of members of their own kind (and maybe members of their own sex). Fairy wrasses are likely to be shy when first added to the aquarium and will usually stay under cover for a while before making their presence known. If not bothered by the aquarist or more aggressive tankmates, they will gradually become more brazen.
Creole wrasses (Clepticus spp.). There are two species in this genus, but only Clepticus parrae makes it into the aquarium trade. It can make a colorful addition to the larger reef or fish-only aquarium. It is not a threat to sessile invertebrates; however, larger individuals may try to consume delicate shrimp. While juveniles can be kept in aquariums as small as 30 gallons, as C. parrae gets larger, it will need to be housed in a tank of at least 135 gallons with plenty of open swimming space. It spends most of its time bobbing about the water column and is a capable jumper, so a tank cover is a must. While the creole wrasse is unlikely to pester larger or more aggressive fish, adults may bully smaller zooplanktivores (e.g., smaller fairy wrasses, flasher wrasses and dartfishes). Although juveniles can be kept in small groups, adult males may fight with each other.
Flasher wrasses (Paracheilinus spp.). These wrasses get their name from the amazing courtship displays performed by the males. When they “flash,” the male soars through the water column with his fins spread and his color intensified. In the aquarium, they spend most of their time in the water column and can serve to encourage shy fish to do the same. Most aquarists keep these fish singly; but flashers are more interesting if kept in small groups that consist of one male and two or more females. All individuals need to be added to the tank simultaneously. It is risky to put more than one male flasher in the same tank, as they are prone to fighting. With the possible exception of their close relatives (e.g., fairy wrasses) or other small planktivores, flasher wrasses are rarely aggressive toward tankmates. They will jump out of an open aquarium. They are more likely to “flash” if kept in groups or if they can see their reflection (a mirror can be placed on the side of the tank to encourage this, as well).
False coris wrasses (Pseudocoris spp.). Members of this genus are occasionally encountered by aquarists. These active fish will need plenty of open swimming space. They tend not to be overly aggressive, though males may pester other zooplankton-feeding labrids. Keep only one male per tank. Juveniles and females can be housed in small groups and may do best if kept in shoals or with other zooplankton-feeding wrasses (e.g., Paracheilinus spp.). New individuals may hide for a day or two, but they typically become bolder with time. If harassed by tankmates, they usually do not survive.
Banana wrasses (Thalassoma spp.). These wrasses tend to be hardy but can also become aggressive in the confines of the home aquarium. Be aware that not all members of this genus feed heavily on zooplankton. Some Thalassoma species, such as the moon wrasse (T. lunare) and sunset wrasse (T. lutescens), have a broad diet and will even eat ornamental invertebrates (e.g., snails, bivalves, worms, urchins, serpent stars and sea stars) and small fish. Most do best in a tank with more belligerent tankmates (though it is usually best to add them to the tank before other bullies). You can add a male and female (one or more), or juveniles to the same tank, if it is larger. They hide among the rockwork at night or when threatened. They are proficient jumpers that will leap out of open aquariums. These are protogynous hermaphrodites (they change sex from female to male), with an initial-phase (juveniles, females and some males) and secondary-phase individuals (“super males”). The colors of these two groups usually differ considerably.