Wrasses
Wrasses
Written by Saturday, 30 November 2002 00:00
Also known as Crenilabrus ocellatus (in Greek cheilou (χειλού)). A very beautiful little fish belonging to the Labridae family, found at depths of 1-30 meters in the Mediterranean sea. Actually it is one of the two endemic species of the Mediterranean Sea. It has a moderately elongated, laterally compressed body with an overall length of 7-13 cm for the male and 4-9 cm for the female. It is a coastal species living in schools over algae-covered rocks and in sea grass beds, although solitary specimens can also be seen. A characteristic of this species is a black blotch below the lateral line on caudal peduncle. Often there is a green ocellus on each operculum, being only faint in yellow-green and orange colour variant. Preopercular margin finely serrated. During the reproductive season (which lasts from May to July) males get aggressive. Males create nests from algae (Cystoseria) which usually have a diameter of approximately 20 cm while juveniles frequently clean other fishes. Those nests can be built quite close to each other. In some places you can find two nests as close as 50 cm from each other – as long as a natural obstacle like a rock blocks the vision of the males. Feeds on bryozoans, hydrozoans, tube worms, shrimps, amphipods and mollusks. It is regarded as a very good species for cold water marine aquaria since it combines some of the virtues that most hobbyists are looking for. A moderate final size, impressive colouration, interesting behaviour and easy acclimatization. In the aquarium it will hide for the first 24-48 hours but will come out in the open water very frequently after that. It will readily accept frozen shrimp, finely chopped shrimp and frozen mysis. It will attack the food by closing in, stopping very close to it (about 5 mm) and then suddenly making a move and taking it in its mouth. It will only keep a small portion of the piece and spit the rest out. This will be done several times till the whole piece is consumed – while the sound of its mouth attacking the water surface can be heard from quite a distance. It will also graze on live rock in a perpendicular position following the same “attack” manner. After a week or so, it develops a “cichlid – like” approach in the sense that it will immediately come to the front glass every time someone passes in front of the tank while at the same time it will beg for food – exactly like a cichlid. It will also dispute the territory of other inhabitants living close to its rock (Salaria pavo being its favourite rival in this aspect) and will hide in the algae when threatened, staying absolutely motionless. After two weeks it is fed with frozen food (once daily) and flakes (twice daily) which it adores (actually it is a "he"). It should be noted that as time in captivity passes by the fish gains more vibrant colours (and size of course). Compare the photos at the bottom row (taken after the fish has spent two months in captivity) to the photos at the middle row (taken one day after collection). This species should be named a “Sea Ostrich” since it has the same habits. Once “hidden” it feels very secure and “invisible” and won’t move even when the net is only some mm away; this allows for easy capturing. When collecting this species it is better to look out for a single specimen to get advantage of this “ostrich” performance. When a large school of those fishes is encountered they will usually run away when you approach them. Collected in April 2002. Definitely a species to watch closely for since I plan to get a female for him.
Second only to Thalassoma pavo this fish shows all the colours in a spectacular horizontal pattern. Indeed, the name “rainbow” is really appropriate. A bit smaller than the Thalassoma pavo will reach a size of 15-20 cm although a maximum size of 25 cm has been reported. The fish will change sexes as it matures and will reach the final (male) stage which is the most colourful of all. The photos show a female fish. This fish is full of energy and will swim all day long patrolling the tank but at the same time it is rather shy. We were able to see those bursts of energy only after the addition of some Thalassoma pavo females, which stay in the open all the time (acting like “dither fish”). Indeed, the C. julis will join them in their play for hours - see photo below showing a C. julis playing with 3 T. pavo females. Frozen shrimp will be readily accepted although commercial food will be ignored for a considerable time. In contrast to T. pavo, this species will bury in the sand almost every night. If you plan to keep it then you should take the precaution of a deep sand bed (5-6 cm will do). As with Thalassoma pavo, their acclimatization is considerably shortened when kept with already acclimatized fish which seem to show them the thereabouts of the tank (feeding time, way of feeding etc.).
Along with Coris juli (the Rainbow wrasse) this is the most colourful fish you will normally see in the Mediterranean and one of the most colourful fishes available to hobbyists. Individuals of these two species also change sex and colour as they mature. However the difference between those two is that in T. pavo even the female colouration (shown in the lower photo) is splendid. The fish can tolerate higher temperatures (even tropical ones) and will reach a size of 28 cm (maximum for adult males). Collecting it in the wild is very easy although patience is needed for adult males. All you need is a rather big hand net (we use one which is 50 cm square) and an open sea urchin. Both T. pavo and C. julis will enter the net after a while to eat the remainders of the urchin. This way you will be able to collect some species in 1-2 minutes. For larger specimens (usually males) you will need to put more than 2-3 urchins in the net and wait till they feel comfortable. Usually, after seeing the smaller fish eating they will enter the net after 5 minutes..
When we take its final size into account it is evident that you need a really big tank (not less than 2 meters long). Will eat frozen shrimps from day one although commercial dry food will be ignored during the first couple of weeks. Will rarely bury in the sand during the night – which makes a sand bed a must. This may be observed by some individuals only – most of them will not do it (another difference from Coris julis). I recommend at least 5 cm of sand although more is better. Although quite large it may be harassed by territorial fish of an equal size. Our male T. pavo had a very nasty “welcome” ceremony by the Salaria pavo which has come to regard the whole bottom of the tank as its territory. It is worthy to note that S. pavo didn’t react to the addition of the female T. pavo although it was about the same time when introduced. Usually there can be only one male per tank. We have currently collected a colony of 6 fishes (one male and five females) of various sizes and we expect them to be fully acclimatized after several months so we will be able to add them to the main marine tank (which will be probably ready by then). The fishes are divided between the two tanks (1 male / 2 females in the left tank and 3 females in the right one). After 3 weeks, most of the females will readily accept even floating flakes – which the male still ignores. All of them will take frozen shrimps and mysis shrimp. Their acclimatization is considerably shortened when kept with already acclimatized fish which seem to show them the thereabouts of the tank (feeding time, way of feeding etc.).
For more information about this species see here.
Read the article on Starting a marine (Mediterranean) tank.
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