is it true that dicrossus filamentosa can change sex???? how true is it?? can somebody verify this!!!!! hehehehe!! thanks... im curiuos and asso worry cos both my filamentosa looks like female except that their size are different! afraid dun have male to breed!
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changing sex?
- Thread starter harnsheng
- Start date
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- 11,222
- Location
- Denver, Colorado, U.S.A.
I have never heard or or seen written reports of D. filamentosus changing sex. Crenicara punctulatum has been reported by some to change sex, & by others not to change sex.
- Messages
- 2,822
- Location
- Stoughton, WI
I have seen sex change in D. filamentosus happen. Here is an article I wrote about it a while ago.
[URL="http://www.cichlidae.info/article.php?id=91"]http://www.cichlidae.info/article.php?id=91[/URL]
I have not had an opportunity to try to repeat the observation. I think that sequential hermaphroditism in Dicrossus may be age-dependent. All the fish I started with were very young. The article is actually more about the topic of sequential hermaphroditism, and I did not go into a lot of detail; mostly because, at the time, I thought that protogenous hermaphroditism in Dicrossus was already known.
Long story short, I had five groups of students set up ten gallon tanks with five young, unsexable fish and raise them until a pair formed. The other three fish were removed and the pairs were allowed to spawn. After the eggs hatched, so we knew they were viable, the males were removed and a female from the reserve tank was placed in with the breeding female. In two of the five tanks the breeding female became male and the new female stayed female.
[URL="http://www.cichlidae.info/article.php?id=91"]http://www.cichlidae.info/article.php?id=91[/URL]
I have not had an opportunity to try to repeat the observation. I think that sequential hermaphroditism in Dicrossus may be age-dependent. All the fish I started with were very young. The article is actually more about the topic of sequential hermaphroditism, and I did not go into a lot of detail; mostly because, at the time, I thought that protogenous hermaphroditism in Dicrossus was already known.
Long story short, I had five groups of students set up ten gallon tanks with five young, unsexable fish and raise them until a pair formed. The other three fish were removed and the pairs were allowed to spawn. After the eggs hatched, so we knew they were viable, the males were removed and a female from the reserve tank was placed in with the breeding female. In two of the five tanks the breeding female became male and the new female stayed female.
- Messages
- 62
- Location
- Cork, Ireland
Sex change has been reported in D. filamentosus but it turned out to be sleeper males showing after the dominant male was removed out of the tank or died. As far as I am aware true sex change has only happened in the species still left in Crenicara.
- Messages
- 11,222
- Location
- Denver, Colorado, U.S.A.
I'm sure that this is the source for most reports of sex changes. For a sex change to be valid, the fish must first have a viable spawn as a female with a male. No other females can be in the aquarium. Then the same fish needs to change sex to a male & successfully fertilize a viable spawn without any other fish in the tank that is a male or possible sneaker male. Such studies are very rare. It is rare in most vertebrates, but does occur (anemonefish). It even occurs in human beings, but I don't know if humans are fertile as both male & female. The most unusual report that I have read is one in which a Caquetia sp. laid eggs in a tank & produced freeswimming fry. It was the only fish in the tank!
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- 64
- Location
- Arcata, CA
Mike Wise said:
Highly interesting!
Might it be possible that somehow the fish was able to store sperm in packets or some other form until such a suitable time came around for it to spawn? Mantis shrimp have that capability, as do some Poecilids.
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- 11,222
- Location
- Denver, Colorado, U.S.A.
Some characids have this ability, too, but I know of no cichlid that is able to store sperm. Since the Caquetia was originally a female that turned to a male, it is more likely that the ovaries were still producing eggs as the testes were devloping & produced sperm.
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- 2,822
- Location
- Stoughton, WI
I have witnessed that with D. filamentosus, by chance and by setting it up to happen. I believe that to see it again I would need to get a hold of a large number of very juvenile fish that are all at the same age.. aka, a spawn...
Basically I had a pair produce fry, then the male died. I had another pair in a separate tank with three much smaller 'females', so I moved the three much smaller 'females' into the tank with the recently widowed female. The breeder fish was 1/2" larger than the three I put in with her. She showed strong territorial dominance immediately. After a week I started to see male coloration on the larger, previously breeding female. After amonth it was a full color and fully finned male. He spawned with the next largest female in the group and the eggs hatched.
I had 25 D. filamentosus at the time. I had gotten them as a group and all were 1/2" inch long. I got them from a store that got 50 of them from a Florida wholesaler/importer. They were too small and fragile for the store to handle, so they sold the surviving fish to me at cost. They were really, really small and thin. Very young. I put five fish each in five ten gallon tanks that my students were maintaining in my classroom. When a pair developed the other fish were moved into a tank without an established pair. After the sex change had been observed once, we (the students and I) purposefully removed males from pairs that spawned and replaced him with fish that had still not developed the color of a male or the red ventral fins of a mature female. We observed the sex change again with two other different females.
No one ever beleives me though. Someday I will manage to find a large spawn of very young fish and do it again. What I need to do is spawn the the species and perform the experiment with the resulting offspring.
