Sexual dimorphism identification of Chelmon rostratus, the Copperband Butterfly,

[OrionN]

From the horse mouth, people who successfully pair, breed and raised Copperband Butterflies

Jirayuth Ruensirikul, Mavit Assava-aree, Atra Chaimongkol, Sirawan Bunchai, and Khwantana Ongart of Coastal Aquaculture Research Institute and Nakhonsithammarat Coastal Fisheries Research and Development Center

Sexual dimorphism identification, pairing and spawning in captivity of wild copperband

butterflyfish, Chelmon rostratus (Linnaeus, 1758) were investigated. Sexual dimorphism

identification was studied by snout morphology comparison of both sexes. The results showed

that the morphology of snout of male and female were differed. The snout of male occupied a

small hump of 1-2 mm height protrusion and higher slope than female. Percent of correct

identification in male and female was differ significantly (p<0.05) that were 83.33% and 100%

respectively. Paring experiment had 5 treatments with 4-6 replications (pairs): male and female

were put in the tank simultaneously (control group: T1), male was put in the tank for 1 week prior

to female (T2), female was put in the tank for one week prior to male (T3), male was placed in

floating basket held in the same tank as female for 1 week before releasing into the tank (T4) and

female was placed in floating basket held in the same tank as male for 1 week before releasing

into the tank (T5). Pairing results of each treatment was significantly different (p<0.05). Percent

of pairing acceptance of T1 (16.67%) was lower than those of T2-T5 (40-100%). Spawning in

captivity of this species was monitored. Spawning data, egg and first 10 days larval development

were recorded. One pair spawned after rearing for 12 months. Number of spawning was 7 times

with 1,940-2,780 eggs per each. The egg was pelagic of 663.00+17.04 μm in diameter with single

oil globule of 132.60+6.30 μm. Newly hatch out larvae was 1.36+0.02 mm of total length. The

mouth was opened at 2 days old at 83-110 μm. Yolk and oil globule were completely absorbed

at 3 and 6 days old respectively. Head spination near pelvic fin was prolonged obviously at 10

days old larvae. This study was revealed the differentiation of sexual dimorphism with snout

shape, successful pairing and spawning in captivity of copperband butterflyfish.

Keywords: Copperband butterflyfish, Chelmon rostratus, sexual dimorphism, paring,

Spawning

With this in mind, I like to have pictures of CBB to see if we can guest if we can correctly sex CBB, or at lease see the differences. I have two that are not in the same tank. Both are doing well. I think I see the differences they are talking about, but I would love to see pictures of these characteristics.
Apparently the sexual dimorphism is minor and does not show until the fish at about 2.5+ inches. Over the next few weeks I will try to post profile pictures of my CBB and see if I can clearly see the differences.

I always love to have a pair of CB in my tank but gave up after several unsucessful tries. With this information, I may try again if I can determine that my two are of different sex.

 

[CollectOyster04]

There's a bonded pair of them at a somewhat local aquarium we frequent. They are housed in a 65,000 gallon display. Of course it's next to impossible to get a real good look at the two for any differences in that tank.
Sometimes it takes a while to locate them, but I could get lost for hours just watching the two of them. Drives my wife and daughter crazy. What would be better than successfully having a Copperband ? Two Copperbands lol. The ones in that ginormous tank are inseparable. They are usually the highlight of my trip.

 

[OrionN]

I would love to be able to get a pair establish. It would be the high light of my tank for sure.
I always love breeding units of fishes. I have harems of Leopards, various angels. I would really want a pair of CBB

 

[Haydn]

I will be watching this. Like you I have tried to pair CBB but have never been successful, with this information I may try again

 

[OrionN]

It seem that even with correctly sexing CBB seem to be only minor part of pairing them. It seem that we need to get them use to each other. Anybody who can get the full article and able to let me know which methods would result in 100% acceptance of the fish? Releasing male and female CBB into the common tank only result in a pair 16.67% of the time

I will attempt to correctly ID the sex my fish, then use an acclimation box for several weeks prior to release the second one into the DT if they are of different sex.

Now I have to clean my aquarium glass so I can get some good pictures.

 

[OrionN]

Quick and dirty profile pictures of the two CBB. I tried my best to take profile pictures. It is hard to do this for the "male" since I only had him for a few months in the QT all these time in the fish room so he is not use to have people looking at him. He tend to hide when I am in the fish room. The "female" I had for several years since she was just about the size of the quarter (not counting the clear tail and the snout. That was almost 3-4 years ago.What do you guys and gals think?

Male I think

Female I think

 

[Tamberav]

What do you think? I see a little bump on the snout midway? Maybe a male?

Mine is also pretty aggressive for a copperband, he got along well with a longnose but he likes to give Tangs hell.

 

[OrionN]

@vetteguy53081

What do you think? I see a little bump on the snout midway? Maybe a male?

Mine is also pretty aggressive for a copperband, he got along well with a longnose but he likes to give Tangs hell.

The angle of the view is so important in determine the slope of the forehead. Your CBB is very healthy. It seem to be a male to me. I would really love to have pictures of paired CBB. If we have these picture, it would really help us learn something.

I hope to have a pair in the near future, contribute some useful information in a few months.

 

[vetteguy53081]

I too am thinking Boy but generally settle what is an educated guess once they are pair up with a potential girl

 

[ThRoewer]

Quick and dirty profile pictures of the two CBB. I tried my best to take profile pictures. It is hard to do this for the "male" since I only had him for a few months in the QT all these time in the fish room so he is not use to have people looking at him. He tend to hide when I am in the fish room. The "female" I had for several years since she was just about the size of the quarter (not counting the clear tail and the snout. That was almost 3-4 years ago.What do you guys and gals think?

Male I think

Female I think

With smaller specimen it is easier to go by the snout angle. Though the first has a clear step where the skull ends and the forehead/back begins. It also has already the steeper forehead slope and the straight to upward tilted snout, all indicators of males.

On the second fish the transition between skull and forehead/back is barely noticeable, the forehead is more sloped, and the snout has a downward tilt. All of that indicates female.

I would put those together in a neutral tank and see what happens. But it might be good to put a clear divider into the tank at first to let them get used to each other. Even if though they are male and female there might be some aggression in the beginning. I had that when I paired some back in the 1990s and also when I paired my Maldives Regals last year. But by now they are often swimming next to each other and all aggression or chasing is gone. With Chelmon you should actually see even more cooperative behavior, similar to what you would see with Rabbitfish where one is the lookout while the other pokes its snout into a crevice to pick food.

 

[OrionN]

Thanks @ThRoewer. I plan to do this in the near future.
Both fish is about the same size.
also I find that there is a clear different between the two fish if I look at the white space at the forehead behind the first orange bar. IMO this is, seem to me, the clearest indication that the fish is male for female.

 

[Jposch]

Thanks @ThRoewer. I plan to do this in the near future.
Both fish is about the same size.
also I find that there is a clear different between the two fish if I look at the white space at the forehead behind the first orange bar. IMO this is, seem to me, the clearest indication that the fish is male for female.

Did you end up following through with this?

 

[i cant think]

Quick and dirty profile pictures of the two CBB. I tried my best to take profile pictures. It is hard to do this for the "male" since I only had him for a few months in the QT all these time in the fish room so he is not use to have people looking at him. He tend to hide when I am in the fish room. The "female" I had for several years since she was just about the size of the quarter (not counting the clear tail and the snout. That was almost 3-4 years ago.What do you guys and gals think?

Male I think

Female I think

I know this is probably a dead thread however, did anyone else realise the body shapes on the males are more elongated than the females?
Could that also be a hint to the sex of the fish

 

[LaloJ]

The more robust appearances in these fish are indicators of males, from what little I have been reading, I suppose that their features are also more elongated, since I find the females with finer and smaller features.

 

[Sshannon]

UF/IFAS IRREC Successfully Aquacultures the Copperband Butterflyfish, Chelmon rostratus! – Rising Tide Conservation

www.risingtideconservation.org

The University of Florida had success with raising wild caught juveniles, and then forcing them breed. They contained the juveniles off in groups of two to four individuals for a period of months to find which individuals would pair with each other. I did not see anything in the article about successful identification of gender through physical identifiers.

 

[OrionN]

According to the authors, once they correctly sexed their CBB, put them together at the same time only result in a pair 16.67% of the time. If they place one of the pair in floating basket held in the same tank, for 1 week prior to release, the pairing rate approach 100%.

 

[Salty_Taste]

According to the authors, once they correctly sexed their CBB, put them together at the same time only result in a pair 16.67% of the time. If they place one of the pair in floating basket held in the same tank, for 1 week prior to release, the pairing rate approach 100%.

This is my new 2in CBB, Would you guess this is a male? Asking because I am receiving another 2in possibly and would like to try throwing them in together and see what happens

Both pics are the same fish.

 

[OrionN]

Recently my LFS brought in two fairly large CBB. I was able to sext the two fish and asked him to put them in one tank separated by a clear divider. If he is able to pair them, I would pay premium for the pair.
Instead of using a divider, he put them in together. This is the two fish after 5 days. One still dominates over the other but not a lot of damages. From the picture below, there are some minor tears on the fins.
The system they are is is a copper based system. No disease that I can see. I plan to bring them home this weekend.

 

[OrionN]

Best I can tell the female in front and male in the back

 

[OrionN]

This is my new 2in CBB, Would you guess this is a male? Asking because I am receiving another 2in possibly and would like to try throwing them in together and see what happens

Both pics are the same fish.

IMO, your fish is still too young to be reliably sexed.