Spawning and parental care in the pink variety of Cichlasoma nigrofasciatum (Gunther) was studied from September 1970 to May 1971. The objectives of the study were to determine: (1) the spawning behavior of C. nigrofasciatum when isolated as pairs; (2) the spawning behavior of a pair when sharing an aquarium with other cichlid species. The study was conducted in two parts.In Part 1 three aquaria were set up, each containing a pair of sexually mature pink convicts. Twelve different pairs were observed over a period of 120 days. Pre-spawning and post-spawning activities were noted. These were recorded in a pictograph form developed by the author. Eight of these activities were observed in the pre-spawning period and 46 were observed during the days following spawning. The interactions between the members of any one pair differed very little from the interactions of any other pair.One spawning was observed from start to finish and every egg placement was recorded. The eggs appeared to be deposited in an irregular pattern, but form a relatively compact mass when the spawning is completed. When a pair is isolated the female cares for both the eggs and the wigglers. The male takes an active role in the care of the fry when they are just starting to swim. The male becomes the more ardent parent once the fry are free swimming and spends much of his time keeping the female in close proximity to the young.In Part 2 the presence of other fishes in the aquarium changed the male's behavior appreciably. He became much more involved in the early post-spawning stages, actively involved in the defense of the eggs and wigglers. These changes were not limited to the male; the female's behavior also changed. She was a much more conscientious parent in the later stages of fry care. The male spent very little time driving the female toward the fry. Both parents became more attentive in Part 2.Six aquaria were used in Part 2. This section placed the pink convicts in aquaria with six other species. The interspecific activity was the prime observation. All of the species observed acted alike. The spawning of several of the species was observed, as was the activity of caring for the young of a different species. The most notable observation here was the similarity of behavior of the cichlids representing three different genera.In both parts all pairs spawned in or on a flowerpot provided. The egg and fry care was almost the same for all of the fishes. The interspecific interactions were as intense as most of the intraspecific. The level of intensity observed declined in the following order: (1) same sex same species; (2) same sex related species; (3) different sex same species; and (4) different sex different species.All of the species in Part 2 that spawned used the same behavioral displays used by the convicts in Part 1. All display with lateral weaving, erected fins, flared opercula, and lowered branchiostegals. All of the spawning pairs attempted to occupy a large territory, but none insisted on more than 5t of their spawning tank. Generally the pairs observed in this study established pair bonds and spawned within two weeks of their introduction to the aquarium.The pink convict lends itself well to this kind of behavioral study because it is a hardy, easy to spawn species large enough to observe easily. They tolerate laboratory conditions very well. The pink variety of C. nigrofasciatum is much less aggressive and more attractive than the native variety.
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/177868 |
| Date | January 1979 |
| Creators | Lundin, Francis C. |
| Contributors | List, James C. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | 3, vi, 79 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
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