Today’s Reef Nuggets deal with a topic very close to my heart. Cirrhilabrus and Paracheilinus, or more commonly known as the fairy and flasher wrasses. Instead of my usual banter on “this ultra rare flasher wrasse” or that “extremely deepwater fairy wrasse”, today’s topic will touch instead, on a more general note. How are these fish found in the wild? How can you, as an aquarist, try to provide the necessary habitats and emulate the behaviour found in nature. I love fairies and flashers, but today’s topic will not have any “OMGs” nor will it have any keyboard smashing. Let’s save that for the next super rare wrasse we see.
Let’s first understand the behaviour and biology of these wrasses. I touched on this briefly in my talk at MACNA this year, but my cringe worthy presentation rife with nerves may have not been the best explanation. Regardless, Cirrhilabrus and Paracheilinus are closely related members of the family Labridae, and are small colourful highly social fish. In the wild, they are found in large aggregations with females greatly outnumbers the males. There are a few important points to note with regards to these fish, and we will touch a little bit more on them as we go along.
Before we begin, let us first look at the social heir achy and behaviour that these fish are known for. Cirrhilabrus and Paracheilinus are closely related, and their biology as well as behaviour are very similar. From this point onwards, all notes will cover both genera unless otherwise specified. After post-larval settlement, juveniles quickly take shelter in the reef and seek out other members of their own kind. Soon, one becomes two, and two becomes four, and eventually a group is achieved. All Cirrhilabrus and Paracheilinus are protogynous sequential hermaphrodites, which means they are all born as females, and males are derived from sex changed females. The individual juveniles and females now having formed a group, will start exerting dominance amongst each other. The most dominant female will start her transformation into a male, complete with secondary male sexual characteristics as well as fully functional sex organs.
As the male grows and develops into a terminal phased male, he starts developing secondary sexual traits. These are a set of characteristics that are found only in males, and not females. Changes depends on the individual species, but usually include bigger finnage, extra filamentous appendages on said finnage, more gaudy coloration, but most importantly, the males develop the ability to flash.
“Flashing” is the termed used to describe a male Cirrhilabrus or Paracheilinus in nuptial display. During flashing episodes, the males spread their fins and swim at great speeds to display to rival males or prospective females. Males develop enhanced coloration, usually with metallic blue or violet patches on their fins and body during flashes, and this coloration is not seen in their relaxed state. Often times, sub-males or satellite males exist in the harem, and live under the dominance of the terminal males. During spawning, these satellite males sometimes sneak up and release gametes just before a mating pair rises, and this enables some fertilisation by the satellite male to take place.
Males flash for two reasons. To pit against rival males, and to attract the attention of females before spawning. Let’s back track a little bit. Remember when we said that females are often found in large groups that live together? Very often, Paracheilinus and Cirrhilabrus are found mixed with other species of their genus. This is especially so for Paracheilinus, where different species are mixed haphazardly in the same territory.
For example, P. filamentosus and P. flavianalis are very often found swimming together, while C. solorensis and C. cyanopleura can be found intermingling above the same reef. To make matters worse, the juveniles and females of many species are nearly indistinguishable, and again, this is especially so for Paracheilinus. To correctly identify a female flasher wrasse in the field, certain contextual clues must be used. For example, the presence of a male, or the geographic range of the species. This will help narrow down your choices but if two very similar species overlap, it is practically impossible to tell.
Throughout this post we have many pictorial examples of Paracheilinus and Cirrhilabrus in the wild, and it is very evident that 1) females outnumber males greatly, and 2) more than one species intermingle in the same habitat. So this brings us back to our original point, where terminal males “flash” to attract the attention of females. The males most definitely are not able to pick out the females of the correct species to spawn with, and so it is up to the females themselves to identify the corresponding males. This is where the “flashing” comes in handy.
There are differences in nuptial colours between each species. Some very obvious, while some are less discernible. This flashing is like a large neon billboard signalling to the females “look at me. I am a male, and I am ready to spawn”. The females recognise the spawning colours and therefore, are able to spawn with the correct species. Flashing therefore helps, to a certain extent, ensure that correct species to species spawning take place. It is this pressure that drives males of some species to evolve, and develop certain unique “nuptial coloration” across different geographical zones. Paracheilinus filamentosus is widespread in many reefs across the pacific, but individual variations in their nuptial coloration exists.
However, because of the haphazard mix of species in close proximity, and the propensity for all these species to spawn at the same time, accidental fertilisation is not uncommon and hybrids arise. When two species nearby release their gametes, accidental cross fertilisation takes place and this leads to hybridisation. Seeing as Paracheilinus is very much the more messy genus, often with two or three different species intermingling together, there are more examples of hybrids from here than Cirrhilabrus. P. flavianalis x P. filamentosus is one of the more common hybrid examples from Indonesia. In Africa, P. mccoskeri x P. attenuatus has been recorded, and P. angulatus x P. lineopunctatus in Luzon. Cirrhilabrus solorensis x C. cyanopleura is an example of a hybrid coming from this genus, but hybrids are rare because Cirrhilabrus does not mix with inter-specifics as much as Paracheilinus.
Having touched upon the behaviour and how they live in the wild, now begs the question. Where do they live? And what kind of habitat do they favour? Cirrhilabrus and Paracheilinus are reef fish, but they are not often found in dense Acropora gardens or high surge reef crests. They are in fact, very fond of rubble slopes or rubble flats, where the reef is largely made up of broken coral with relatively flat, unobstructed swimming areas.
The low lying substrate enable the males to swim freely at high speeds to display their fins with full effect. The lose rubble provides numerous hiding spaces for the females as well when threat arises. Apart from Cirrhilabrus and Paracheilinus sharing the same habitat and mingling inter-generically and inter-specifically, the rubble reef is also home to other fish that live in harmony with these wrasses.
Take a look at this beautiful video by BlennyWatchers featuring Cirrhilabrus humanni in the wild. This is a perfect summary of everything we’ve been discussing so far.
1) Habitat – Notice the large expanse of sandy rubble that this video is filmed in.
2) The mixing of wrasses – Notice the hoard of females swimming amongst the rubble, and also take special note on the number of species found here. The females are largely similar and impossible to differentiate, but the presence of male Cirrhilabrus humanni, Cirrhilabrus filamentosus and Paracheilinus flavianalis points towards at least three species, in two different genus mixing haphazardly in the same habitat.
3) Flashing and Nuptial display – The video clearly shows Cirrhilabrus humanni and Paracheilinus flavianalis in their nuptial display, and also shows a comparison in coloration of the species before and after flashing. Notice how both fairies and flashers display at the same time, in the same reef. This is what we were mentioning before with regards to simultaneous spawning, giving rise to hybrids. In this case, P. flavianalis will not form hybrids with C. humanni, but if another flasher wrasse, for example P. filamentosus were to engage in spawning at this time, then possible hybrids may occur due to cross fertilisation. And finally,
4) Habitat fauna – The rubble reef is usually devoid of large coral structures. Isolated patches of soft coral and stony corals are peppered here and there. In some rubble reefs like those in Kwajalein atoll, Halimeda algae is the primary ground cover, and in that habitat, is home to Cirrhilabrus rhomboidalis and Cirrhilabrus johnsoni. Also take note of the other fish living in the same rubble patch. Pomacentrus auriventris, Centropyge flavicauda and Macropharyngodon negrosensis to name a few.
So how does this information help us, the aquarist, keep and maintain Cirrhilabrus and Paracheilinus? Many people are drawn to the bright colours and beautiful finnage of male fairy and flasher wrasses. However as you have seen, the males develop these traits in response to dominance over a large harem of females. Without the duller females, many males fail to either flash, or keep their coloration in the home aquaria.
It is therefore highly recommended that females are purchased along with the males. Alternatively, it is possible to start a harem yourself with only females, and wait for the most dominant one to change into a male. Don’t be afraid to mix your species together, provided your tank is large enough. Emulate the natural setting of these fish in the wild. The presence of different Cirrhilabrus and Paracheilinus in your harem will stimulate rivalry between males, and again, to prevent any serious injury, a large tank should be used.
Alternatively, for an interesting and unorthodox set up, a species specific biotope would be nice. Replicate the same rubble reefs using broken coral or dead Fungia. Keep a harem of largely females, and a single male of a species you like the most, and then add in other fish fauna that live in close association. It could be fun, and would make for an interesting display.