Scott's Fairy Wrasse aggression?

[Ninong]

Question for anyone who has experienced problems with getting the resident Scott's Fairy Wrasse (Cirrhilabrus scottorum) to accept a newcomer.

I received a gorgeous mature pair of Australian variant Scott's Fairy Wrasses on Dec. 17th. Unfortunately only the female survived the shipping stress. The supermale was 5.5" long and the female was approximately 4"-4.5" long. The female had typical Australian variant adult female coloration and the supermale had very obvious supermale coloration and features.

The vendor offered to replace the lost supermale with another from his next shipment. This is where I made a major mistake. I asked the vendor to please select another gorgeous supermale for me and he agreed to choose the nicest one from the next shipment. In retrospect I should have played it safe and requested a 3.5" female.

The replacement male arrived Jan. 23rd. He appears to be about 4.75" long (guessing) and has typical supermale coloration: Dark blue dorsal fin and elongated pelvic fins with dark blue edges. I did an extremely slow acclimation (9 hours) and released him into the tank at 10:30 p.m. after all of the other fish were sound asleep and the lights had been off for hours.

At 8:00 a.m. the following morning the actinics came on. At 8:05 a.m. all hell broke loose in the tank. The resident "female" Scott's was chasing the new male all over the tank, into and out of the live rock, under the live rock, etc. There was sand throughout the water column. Because the new guy was weak from shipping stress and unfamiliar with the tank, the resident "female" was able to outswim him and was constantly biting him on top of his head at the base of the dorsal fin. This first high speed chase lasted a full ten minutes, maybe more, until the male finally wedged himself into a narrow rock crevice.

My problem is that my female grew at least 1/2", maybe more, in the five weeks she was in the tank without a male's presence and began to take on male coloration: She began to develop a dark blue line at the anterior dorsal fin running the full length of the fin and meeting up with the wide streak of dark blue she already had at the posterior third of the fin. My previous supermale and the new fish both had/have the typical Australian variant dark blue dorsal fins.

There were two high speed chases in the tank the first day. The second one lasted about two or three minutes. The third chase took place the following day and lasted maybe 10 seconds. The male has spent all of his time in hiding since I received him. The "female" (almost certainly a male at this point) swims over to where he is hiding out and displays in front of his hiding place with fully erect fins and a little dominance dance -- back and forth motion for three or four seconds. "She" did this all day long, hundreds of times a day, for the first week. Now she simply swims over to make sure he is inside his cave but doesn't bother with the dominance display.

The new male did not eat anything for the first six days in the tank even when I placed food within an inch of his mouth. For the past three days he has been eating a little whenever the "female" is busy at the other end of the tank feeding. It's only a 120-gal tank. The resident "female" has taken to patrolling the surface of the tank. The entire tank is now her/his territory.

Today is the 10th. day since I placed the new male in the tank. He is still alive. He has constructed a large sand foxhole under the live rock at the right front of the tank so that he can move around inside it. The excavated area is about 10" across. This is not a problem for the stability of the rock structure because the rocks rest on a support structure within the 7" deep sand bed. I did get a good look at the male yesterday morning when he ventured out of his cave for about three or four seconds to grab some food while the "female" was busy eating. The front 2/3 of his dorsal fin has been chewed away. All he has remaining is about a 1/8" jagged ridge sticking up from his body where the dorsal fin used to be. He still has some of the posterior part of the dorsal fin intact. His other fins appear to be intact. Evidentally the "female" has been attacking him inside the cave.

Finally the question: Has anyone had a mature male Scott's revert to female in response to conspecific aggression?

I have considered trying to remove the "female" temporarily to a quarantine tank but I have been warned that this could very well kill the "female" and would only delay the inevitable confrontation once I tried to put her back into the tank. In fact, since the new male would presumably be healthier and in better condition, it might be an even more violent confrontation. It is not possible for me to partition off a section of the tank to isolate the aggressive fish because my live rock structure extends across the full tank.

My only hope at this point is that the new male will revert to female and be accepted by the resident aggressor. Either that or he will die. According to information I read online, it appears that a mature female Cirrhilabrus sp. fairy wrasse can change from female to male within 12-20 days in the absence of a controlling male influence. I was unable to find anything on the length of time it takes for a male to revert to female. The only references I found were anecdotal reports that this has been observed in captivity. I'm not sure it the reports apply to so-called supermales or just subordinate males.

I have discussed this situation with several different people familiar with the behavior of Scott's fairy wrasses and the consensus of opinion seems to be that the new fish is going to die. I am hoping someone else has had better luck and can tell me that their incoming male reverted to female and survived.

Thanks!

[Poseidon]

WOW!!! Sounds like the poor guy is doomed. Rather then let that happen have you considered trading him in at a LFS? I know you won't get what you paid, but maybe you can get something. Then this poor guy will get a CHANCE, rather slim at a LFS I know, but better then getting his tail kicked everyday.

From your description and my confidence that you have done everything you can, I think this is the last resort so to speak.

In any case, Good luck I hope it works out.

Mike

[Ninong]

A lot has changed since I posted that a couple of days ago. For one thing, I have done a lot more research on sexual determination in fairy wrasses. I believe I had confused fairy wrasses with Pseudanthias spp. in believing it might be possible for a male to revert to female under certain conditions. Both are haremic protogynous hermaphrodites but the consensus of opinion seems to be that terminal phase male fairy wrasses are incapable of reverting back to female. It's possible I may be confused about Pseudanthias, too. Perhaps it is only the subordinate males that revert to female under the right circumstances -- too many males, not enough females.

This raises an interesting possibility. Perhaps my "female" Scott's has not completed the transformation to male, yet. After all, her dorsal fin is still mostly the typical female bright orange coloration. It is not yet mostly dark blue like a typical Australian variant Scott's male. When I received my original pair back on Dec. 17th. there were obvious differences between the supermale and the female besides the fact that the supermale was about 5.5" long and the female was maybe 4" long (just guessing on the female's size since I did not measure her). I have confidence in the vendor's ability to recognize a female and believe that he selected the best available supermale and paired it with the largest adult female in that batch of 20 fish. So I am fairly certain that my "female" was actually a female when I got her. I don't know if she would begin changing into a male in the absence of another male although adult Centropyge spp. angelfish seem to do that in the absence of a male and clownfish seem to become females (their terminal gender) in the absence of another female.

I assumed that my female had changed because she had grown noticeably in the five weeks between the time I got her and the time I received a replacement for my deceased supermale. I also read somewhere that the dominant female in a group of fairy wrasses can become a male in 12-20 days following the loss of the supermale. But there is a difference between that situation and my situation. In that situation there would be pressure to complete the transformation quickly because of the presence of the other female members of the group. Maybe it doesn't proceed that fast in an aquarium without social interaction with conspecifics.

If I am lucky, my female has not yet completed the transformation to male and the process could possibly be halted by interaction with a male Scott's. I believe she would have been aggressive towards any new Scott's that was introduced into the tank, whether it was a male or a female, unless it was a considerably larger fish. That's why you always see the recommendation that pairs be added at the same time or, if that's not possible, then the smaller fish should be added a couple of weeks before the larger fish.

My new male Scott's surprised me yesterday afternoon by leaving his foxhole tunnel system under the live rock and swimming freely in the tank. This was his 11th. day in the tank and the first time he had attempted this since the first couple of days. There is no question about the injuries he sustained to his dorsal fin. The front half of his dorsal fin is chewed down about halfway so that all of the dark blue is missing and the back half is frayed. He has several bite marks on the top of his head near his dorsal fin. The rest of his fins, including his caudal fin, appear to be intact. There are no open wounds as such on his body. His coloration is similar to the female's except it is more intense. His caudal fin is a little bit redder than hers. Hers is more of a red-orange compared to his. And his dorsal fin was mostly dark blue when he arrived. Her dorsal fin has a wide streak of dark blue in the posterior half but it is still predominately the typical female bright orange. There is a new narrow streak of dark blue that has formed at the anterior edge of her dorsal that runs back towards the wider patch of dark blue but it does not compare to the amount of dark blue that the male has or that the previous male had.

The male is either the same length or slightly longer than the female. The female appears to be slightly heavier than the male. It is hard for me to judge sizes while they are in the tank. I underestimated the size of the original supermale and was surprised when I measured his dead body to find that he was a bit longer than 5.25" dead. I think he was at least 5.5" alive. At first I though my female Scott's was only about 3.5"-4" when I got her but after measuring the dead male I decided that the female was probably 4"-4.25" when I got her. I believe that the female is now about 4.75" long. My best guess today, after seeing my new male for a longer period of time, is that he is about 5" long.

I first noticed the male swimming freely in the tank around 4:30 p.m. yesterday. I deliberately fed the tank twice in the next two hours to see what would happen. The female totally ignored him while she was eating. She did attempt to run him off a few times but not with the ferocity that she displayed previously. She did not attempt to bite him on the head or the dorsal fin like she did every time he came out before. The male was wary of the female but not scared to death like he was when he first arrived. There were no high-speed chases.

Today the male is swimming in the tank again and the female is attempting to display dominance but he is pretty much ignoring her and she is being much more cautious in her aggression. After the first couple of days when the female tried to kill the newcomer, I reduced the photoperiod on the tank to allow the new guy more time to rest or at the very least reduce the daylight period that she would have to pick on him. I have been deliberately feeding the tank heavily and positioning food in front of his cavern to try to get him to eat. He refused to eat the first five or six days even when food was only an inch from his mouth. He has been eating for the past five days or so but yesterday was the first time he ventured more than a few inches out of his cavern.

I don't know what's going to happen next. I am hoping that I end up with a male-female pair. In order for that to happen, the new male will have to start asserting dominance. If he doesn't, then I fear the resident female will complete her transformation to male and I will have a problem on my hands.