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Something I only touched on briefly in the reading, and didn't get to in the chat. Also, in the interest of making this forum an integral part of the class, and not just a bulletin board, here we go...
This gets a bit confusing, I even have to correct myself as I type since I often type mix them up myself…protanderous, protogynous, protanderous, protogynous….but once you understand the basic mechanism it should fall into place for you.
As stated, hermaphroditism manifests in different ways among freshwater and marine fish.
Simultaneous hermaphroditism, in which a fish carries both male and female organs. You're not likely to be keeping more than one specimen of the few fish that exhibit this form hermaphroditism, although there possibilities, such as the Hamlets.
Sequential hermaphroditism (the more common of the two) in which all individuals start out either as one sex, and later may change depending on social and/or environmental conditions.
With Protanderous Hermaphrodites, the rarer of the two mechanisms, all individuals start out as males, and only the dominant individual will become a female.
With Protogynous Hermaphrodites, all individuals start out as females, later changing to males as social and environmental factors dictate - generally meaning dominance, same as above. Sometimes you will have a "Supermale", and a few other sub-dominant, non-reproductive males present.
In either case, you can have pair bonding or harem behavior depending on the species. The latter case being where multiple individuals of one sex live in close proximity to the single dominant individual of the opposite sex...this would mean a dominant female in the case of a protanderous species, or dominant male in the case of a protogynous species.
So, either a dominant male surrounded by females, or a dominant female surrounded by males, to simplify things. Or, you simply end up with multiple pairs spread out over the territory.
In your dabblings into this hobby, you'll most likely be exposed to this phenomenon through the genus' Amphiprion or Premnas (the Tomato Clown being the only species in the latter genus). Although markedly more difficult to breed, their damselfish brethren are also examples of a sequentialy protanderous species. Perhaps you’ll witness this phenomenon with the Dottybacks of the genus Psuedochromis, a non-harem spawning protogynous species.
Another favorite group among marine aquarists, the dwarf angelfish of the genus Centropyge exhibit harem protandery, which is actually the more common of the two mechanisms, and as stated above occurs with the Dottybacks as well. A great thing to attempt would be a largish tank with a group of P. fridmani, the Orchid Dottyback. You’ll see pairs form, and “extra” individuals can then be removed…not that catching a Dottyback is an easy thing. Provided you have the space, you can also simply let them be and multiple pairs will form and stake out territories.
Protanderous hermaphroditism also occurs in fish such as wrasses and groupers, however you won’t be keeping pairs of these fish in all likelihood since doing so generally poses difficulties.
Protogynous sequential hermaphroditism can be easily observed in certain freshwater fish of the family cichlidae. This is where my genesis as fishkeeper lies, so I have a soft spot for the family in general. Anyhoo... Here, all fry (baby fish) start live as females, and only the dominant individual of the group will become a male. This is because in Lake Malawi, resources are abundant. The awfwuchs (encrusted algae, small organisms) that cover the constituent rocks of their environment is of endless supply. Food is not a problem, so it makes sense for multiple reproductive females to be served by one male.
On the other hand, with clownfish that are limited to the shelter provided by the host anemone, and since to the food items in that small microhabitat are limited, and since producing eggs takes energy - it therefore makes sense that a single reproductive female is serviced by a single reproductive male, with non-reproductive males waiting in “reserve”.
What we have then with regard to clownfish in the wild is a colony, or harem situation whereby there is a large, dominant female, a smaller male, and a group of even smaller males that do not spawn with the female. Should the reproductive male be removed, the next dominant male will take his place. Should the female be removed, the reproductive male will then become a female, with the male just below him in the pecking order becoming the new reproductive male. Simple eh?
With regard to captive husbandry then, forming a pair of clownfish is usually very simple. You simply buy a group of unrelated youngsters, say in the 1” to 1.5” range or so. You grow them up, and a dominant female will emerge, and pair up with a male. The other individuals can then be removed.
It gets a bit tougher with an aggressive species such as the Tomato Clown, if you already have a large established female in the system. If you then wish to form a pair, you may have a challenge on your hands. This is an aggressive species, and the female will normally tear to shreds any small male you introduce in short order. What to do then?
What has worked well for me in the past is the “shark cage “ approach, and multiple anemones in the system. You simply place the male in a clear plastic container with many holes drilled in it for circulation. You place this container near the female and just wait it out. You’ll see her display at him, attempt to bite him…let’s not kid ourselves…KILL him, but her effort will be all for naught, since you’ve protected the little guy in his happy clear girl proof home!
After a day or two you’ll notice that she starts to ignore him more or less, or least her attentions in his direction cease to be aggressive in nature. This is when you let the little guy loose. Chances are she’ll bat her tail at him a few times, maybe mouth him a little bit, but all should be well within a few minutes. This is also where multiple anemones comes in…he can move between them and get away from her if he needs to while not leaving the security of an anemone. While not necessary to have these extra anemones, it’s certainly an added measure of safety which seems to have helped a time or two in my experience.
The sex of a single specimen kept by itself of any sequentially hermaphroditic species will reflect the type of hermaphroditism displayed within that species. So, if you have a single Flame Angle, a protogynous hermaphrodite, then you’ll have a male on your hands. If you have a single Clarkii Clownfish, then you’ll have a female.
Although clownfish are generally harem spawners, pairs generally work best in captivity.
A trio of dwarf angels can work well, two males to one female…as two males will kill each other.
Dottybacks are another pair bonding species, no harems here...they're one of those "sanctity of marriage" species...ya know?
That's all for now...see you all Sunday night!
Feel free to discuss or ask questions.
Going forward we'll overflow what we didn't get to in chat here, or can post new questions you come up with, or answer each other's queries if you so desire.
Jim
This gets a bit confusing, I even have to correct myself as I type since I often type mix them up myself…protanderous, protogynous, protanderous, protogynous….but once you understand the basic mechanism it should fall into place for you.
As stated, hermaphroditism manifests in different ways among freshwater and marine fish.
Simultaneous hermaphroditism, in which a fish carries both male and female organs. You're not likely to be keeping more than one specimen of the few fish that exhibit this form hermaphroditism, although there possibilities, such as the Hamlets.
Sequential hermaphroditism (the more common of the two) in which all individuals start out either as one sex, and later may change depending on social and/or environmental conditions.
With Protanderous Hermaphrodites, the rarer of the two mechanisms, all individuals start out as males, and only the dominant individual will become a female.
With Protogynous Hermaphrodites, all individuals start out as females, later changing to males as social and environmental factors dictate - generally meaning dominance, same as above. Sometimes you will have a "Supermale", and a few other sub-dominant, non-reproductive males present.
In either case, you can have pair bonding or harem behavior depending on the species. The latter case being where multiple individuals of one sex live in close proximity to the single dominant individual of the opposite sex...this would mean a dominant female in the case of a protanderous species, or dominant male in the case of a protogynous species.
So, either a dominant male surrounded by females, or a dominant female surrounded by males, to simplify things. Or, you simply end up with multiple pairs spread out over the territory.
In your dabblings into this hobby, you'll most likely be exposed to this phenomenon through the genus' Amphiprion or Premnas (the Tomato Clown being the only species in the latter genus). Although markedly more difficult to breed, their damselfish brethren are also examples of a sequentialy protanderous species. Perhaps you’ll witness this phenomenon with the Dottybacks of the genus Psuedochromis, a non-harem spawning protogynous species.
Another favorite group among marine aquarists, the dwarf angelfish of the genus Centropyge exhibit harem protandery, which is actually the more common of the two mechanisms, and as stated above occurs with the Dottybacks as well. A great thing to attempt would be a largish tank with a group of P. fridmani, the Orchid Dottyback. You’ll see pairs form, and “extra” individuals can then be removed…not that catching a Dottyback is an easy thing. Provided you have the space, you can also simply let them be and multiple pairs will form and stake out territories.
Protanderous hermaphroditism also occurs in fish such as wrasses and groupers, however you won’t be keeping pairs of these fish in all likelihood since doing so generally poses difficulties.
Protogynous sequential hermaphroditism can be easily observed in certain freshwater fish of the family cichlidae. This is where my genesis as fishkeeper lies, so I have a soft spot for the family in general. Anyhoo... Here, all fry (baby fish) start live as females, and only the dominant individual of the group will become a male. This is because in Lake Malawi, resources are abundant. The awfwuchs (encrusted algae, small organisms) that cover the constituent rocks of their environment is of endless supply. Food is not a problem, so it makes sense for multiple reproductive females to be served by one male.
On the other hand, with clownfish that are limited to the shelter provided by the host anemone, and since to the food items in that small microhabitat are limited, and since producing eggs takes energy - it therefore makes sense that a single reproductive female is serviced by a single reproductive male, with non-reproductive males waiting in “reserve”.
What we have then with regard to clownfish in the wild is a colony, or harem situation whereby there is a large, dominant female, a smaller male, and a group of even smaller males that do not spawn with the female. Should the reproductive male be removed, the next dominant male will take his place. Should the female be removed, the reproductive male will then become a female, with the male just below him in the pecking order becoming the new reproductive male. Simple eh?
With regard to captive husbandry then, forming a pair of clownfish is usually very simple. You simply buy a group of unrelated youngsters, say in the 1” to 1.5” range or so. You grow them up, and a dominant female will emerge, and pair up with a male. The other individuals can then be removed.
It gets a bit tougher with an aggressive species such as the Tomato Clown, if you already have a large established female in the system. If you then wish to form a pair, you may have a challenge on your hands. This is an aggressive species, and the female will normally tear to shreds any small male you introduce in short order. What to do then?
What has worked well for me in the past is the “shark cage “ approach, and multiple anemones in the system. You simply place the male in a clear plastic container with many holes drilled in it for circulation. You place this container near the female and just wait it out. You’ll see her display at him, attempt to bite him…let’s not kid ourselves…KILL him, but her effort will be all for naught, since you’ve protected the little guy in his happy clear girl proof home!
After a day or two you’ll notice that she starts to ignore him more or less, or least her attentions in his direction cease to be aggressive in nature. This is when you let the little guy loose. Chances are she’ll bat her tail at him a few times, maybe mouth him a little bit, but all should be well within a few minutes. This is also where multiple anemones comes in…he can move between them and get away from her if he needs to while not leaving the security of an anemone. While not necessary to have these extra anemones, it’s certainly an added measure of safety which seems to have helped a time or two in my experience.
The sex of a single specimen kept by itself of any sequentially hermaphroditic species will reflect the type of hermaphroditism displayed within that species. So, if you have a single Flame Angle, a protogynous hermaphrodite, then you’ll have a male on your hands. If you have a single Clarkii Clownfish, then you’ll have a female.
Although clownfish are generally harem spawners, pairs generally work best in captivity.
A trio of dwarf angels can work well, two males to one female…as two males will kill each other.
Dottybacks are another pair bonding species, no harems here...they're one of those "sanctity of marriage" species...ya know?
That's all for now...see you all Sunday night!
Feel free to discuss or ask questions.
Going forward we'll overflow what we didn't get to in chat here, or can post new questions you come up with, or answer each other's queries if you so desire.
Jim
