kaybee
07-11-2008, 03:56 PM
With most Lake Malawi (and other rift lake) cichlid species, the fish are hiearchal in nature with an established pecking order. This pecking order is not permanent and can be changed via aggression.
Here are some instances documenting same-species sub-dominant males seizing the alpha male position from the dominant male.
Nimbochromis venustus ('giraffe cichlid').
These males were part of a small group of vensutus' acquired as tiny juveniles. From the start one grew faster than all the others and established itself as the 'alpha male' venustus in the tank. The second male was regulated into the postion of 'beta-male'. Subordinate venustus males display their blotched or 'giraffe' patterns, patterns which are absent among the alpha-males. The alpha would regularly pursue the beta male but nothing physical became of it.
As they put on size (~6") the beta male began challenge-attempts toward the alpha, but the alpha easily maintained his position. Over time and incrementally, however, the beta male made significant strides towards becoming the alpha. For some unknown reason, the beta male would assume the alpha role when the tank lights were on, and the actual alpha maintained dominance when the tank lights were off. The beta male was actually much more aggressive when the lights were on than the other alpha was when the lights were off, so I kept the lights off most the time to help keep aggression down to acceptible levels. Up to this point there were no battles, only one-sided pursuits (with the alpha male pursuing the blotched sub-dominant, but no physical contact).
Then the ambitious beta male ramped up its efforts and began to challenge the alpha male even when the lights were off (which meant it was attempting to become the full time alpha male, regardless of lighting conditions). When this occurred both males, 7"-8" at this point, simultaneously shifted into dominant colors an physically engaged each other in a lip-locking test of strength (the challenging 'upstart' is on the right):
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Eventually, after several bouts, the challenger defeated the former alpha male (forcing the ex-dominant to permanently revert to the submissive blotched pattern). Unlike the defeated male (which would focus its attention toward the females after previously dominating the other male), the new alpha began to not only continously harass the first male, but also terrorize the females and all of the other fish in the tank. He went from being the passive #2 male to becoming the tank tyrant. I eventually sold the new alpha male and peace was restored.
Metriaclima sp. zebra "Chilumba" (Black-barred zebra)
As with the venustus', these were purchased as a group and one male outgrew the others and became the dominant early one. When matured, the alpha male displayed a vibrant striped pattern (as seen in my avatar). The sub-dominant male was pressured to remain in submissive patterns (mostly solid purple-blue), and was tolerated by the alpha male as long as it remained in that color-scheme.
Then a similar sequence of events experienced with the venustus' began to occur (i.e., lighting conditions being some sort of 'catalyst'), the beta male zebra would shift into dominant colors when the lights were off and the alpha male would become submissive and revert to solid purple coloration. This role reversal could literally occur at the flip of a light switch. Occasionally they would 'display' at each other, both in full dominant coloration but wouldn't engage in any physical activity.
As with the venustus, the challenger then began to display dominance regardless of lighting conditions and tested the alpha male. Interestingly, during the confrontation, both males shifted into submissive colors, rather than dominance coloration:
[Only Registered Users Can See Links.]
Once defeated, the ex-alpha reverted into permanent submissive colors. Unlike the vensutus', the new alpha male accepted the defeat and tolerates the former dominant fish to this day. They have an 'understanding' of a sort: peaceful coexistance so as long as the ex-alpha doesn't display his striped pattern. I'm thinking of moving him to another tank (where he'll be the only one of his species) so that his beautiful colors can once again shine.
Finally,
Dimidiochromis compressiceps (malawi eye biter)
Unprecedentedly, my two males lip-locked this past week, something I've never seen them do before (they've been together for years). It's hard to gauge their size in this pic, but they're currently in the 9"-10" size range, so if it intensifies I'll have to remove one of them. In the past I've only seen them occasionally 'display' (no pursuits or physical contests). I'm not sure which one is the dominant since they've never adhered to a pecking order.
[Only Registered Users Can See Links.]
Based on what I've seen, a 'de-throned' alpha male remains subordinate as long as the new male remains in the tank (demotion is permanent); many former-alpha males fall considerably down in the tank's hierarchy: #1 fish gets beaten by #2 fish; #2 becomes the new #1, the former #1 drops to #7 or even lower, rather than dropping only to #2. It's interesting how the rest of the tank senses the change in status (for example #4 fish in the pecking order suddenly has the ablility to dominate the the former-alpha without having to 'earn' that right).
Despite the violence depicted in the photo's, the lip-locking males weren't harmed (even though the sounds of their clash were quite audible outside the tank, sounds like someone biting their nails). The potential for injuries (or worse) only greatly increases if the situation transitions from 'evently matched' to a 'one-sided damage-inflicting hyper-domination' with intent to eliminate.
Here are some instances documenting same-species sub-dominant males seizing the alpha male position from the dominant male.
Nimbochromis venustus ('giraffe cichlid').
These males were part of a small group of vensutus' acquired as tiny juveniles. From the start one grew faster than all the others and established itself as the 'alpha male' venustus in the tank. The second male was regulated into the postion of 'beta-male'. Subordinate venustus males display their blotched or 'giraffe' patterns, patterns which are absent among the alpha-males. The alpha would regularly pursue the beta male but nothing physical became of it.
As they put on size (~6") the beta male began challenge-attempts toward the alpha, but the alpha easily maintained his position. Over time and incrementally, however, the beta male made significant strides towards becoming the alpha. For some unknown reason, the beta male would assume the alpha role when the tank lights were on, and the actual alpha maintained dominance when the tank lights were off. The beta male was actually much more aggressive when the lights were on than the other alpha was when the lights were off, so I kept the lights off most the time to help keep aggression down to acceptible levels. Up to this point there were no battles, only one-sided pursuits (with the alpha male pursuing the blotched sub-dominant, but no physical contact).
Then the ambitious beta male ramped up its efforts and began to challenge the alpha male even when the lights were off (which meant it was attempting to become the full time alpha male, regardless of lighting conditions). When this occurred both males, 7"-8" at this point, simultaneously shifted into dominant colors an physically engaged each other in a lip-locking test of strength (the challenging 'upstart' is on the right):
[Only Registered Users Can See Links.]
Eventually, after several bouts, the challenger defeated the former alpha male (forcing the ex-dominant to permanently revert to the submissive blotched pattern). Unlike the defeated male (which would focus its attention toward the females after previously dominating the other male), the new alpha began to not only continously harass the first male, but also terrorize the females and all of the other fish in the tank. He went from being the passive #2 male to becoming the tank tyrant. I eventually sold the new alpha male and peace was restored.
Metriaclima sp. zebra "Chilumba" (Black-barred zebra)
As with the venustus', these were purchased as a group and one male outgrew the others and became the dominant early one. When matured, the alpha male displayed a vibrant striped pattern (as seen in my avatar). The sub-dominant male was pressured to remain in submissive patterns (mostly solid purple-blue), and was tolerated by the alpha male as long as it remained in that color-scheme.
Then a similar sequence of events experienced with the venustus' began to occur (i.e., lighting conditions being some sort of 'catalyst'), the beta male zebra would shift into dominant colors when the lights were off and the alpha male would become submissive and revert to solid purple coloration. This role reversal could literally occur at the flip of a light switch. Occasionally they would 'display' at each other, both in full dominant coloration but wouldn't engage in any physical activity.
As with the venustus, the challenger then began to display dominance regardless of lighting conditions and tested the alpha male. Interestingly, during the confrontation, both males shifted into submissive colors, rather than dominance coloration:
[Only Registered Users Can See Links.]
Once defeated, the ex-alpha reverted into permanent submissive colors. Unlike the vensutus', the new alpha male accepted the defeat and tolerates the former dominant fish to this day. They have an 'understanding' of a sort: peaceful coexistance so as long as the ex-alpha doesn't display his striped pattern. I'm thinking of moving him to another tank (where he'll be the only one of his species) so that his beautiful colors can once again shine.
Finally,
Dimidiochromis compressiceps (malawi eye biter)
Unprecedentedly, my two males lip-locked this past week, something I've never seen them do before (they've been together for years). It's hard to gauge their size in this pic, but they're currently in the 9"-10" size range, so if it intensifies I'll have to remove one of them. In the past I've only seen them occasionally 'display' (no pursuits or physical contests). I'm not sure which one is the dominant since they've never adhered to a pecking order.
[Only Registered Users Can See Links.]
Based on what I've seen, a 'de-throned' alpha male remains subordinate as long as the new male remains in the tank (demotion is permanent); many former-alpha males fall considerably down in the tank's hierarchy: #1 fish gets beaten by #2 fish; #2 becomes the new #1, the former #1 drops to #7 or even lower, rather than dropping only to #2. It's interesting how the rest of the tank senses the change in status (for example #4 fish in the pecking order suddenly has the ablility to dominate the the former-alpha without having to 'earn' that right).
Despite the violence depicted in the photo's, the lip-locking males weren't harmed (even though the sounds of their clash were quite audible outside the tank, sounds like someone biting their nails). The potential for injuries (or worse) only greatly increases if the situation transitions from 'evently matched' to a 'one-sided damage-inflicting hyper-domination' with intent to eliminate.