回首頁 > 文件夾 > 繁殖缸 >
Pelvicachromis humilis, A Breeding Account for a Very Large 'Krib'
|作者 Ted Judy, 2006.|
Get the full color PDF of this classic now out of print book!
The genus Pelvicachromis was originally described in 1968 by Thys van den Audenaerde, D. F. E. using P. pulcher (Boulenger, 1901) as the type species. P. pulcher is such a well known and commonly kept dwarf cichlid that many hobbyists are not aware that the Pelvicachromis genus is a very diverse. The genus is popularly divided into two groups of species, Type 1 and Type 2. Type 2 species include the familiar P. pulcher, P. taeniatus, P. subocellatus, and P. roloffi. Type 1 species include the larger and less common (in the hobby) P. humilis, P. signatus and P. rubrolabiatus. Type 1 Pelvicachromis are characterized by being larger and having a more elongated face with a more downward oriented mouth.
P. humilis is a diverse species with several recognized geographic forms. Male P. humilis reach approximately 12 cm in length while females are smaller. Male P. humilis are generally brown or tan in color with a series of eight vertical bars that appear and disappear depending upon mood. Some geographic forms may have a lateral stripe as well as the vertical barring. The darkness of these ornaments, and the mood in which they appear, varies between the different regional forms. A male's unpaired fins will usually have some red coloration. The caudal fin is usually rounded to rhomboid, and older males may develop a few longer rays in the upper portion of the caudal fin. Females are mostly a silvery-gray color with a rosy abdomen that gets darker when ripe. The female's pectoral fins are more rounded than those of the male, as is consistent with all species in the genus. The upper portion of the female's caudal fin is an attention-grabbing iridescent silvery-blue.
P. humilis has a range that extends from Guinea to Liberia. Their habitat includes small rivers and larger streams in forested areas where trees shade the water. P. humilis is more aggressive than the Type 1 species, as well as being considerably larger, and therefore need more space. The species tends to be quite shy for a longer period of time than other Pelvicachromis species, and ample hiding places are necessary for them to feel comfortable.
I obtained my P. humilis pair in November of 2005. The male was approximately 8 cm long and the female 5 cm long. I keep them in a 40 gallon breeder tank, initially with some young Cryptoheros sajica. The other cichlids acted as dithers and target fish for the male P. humilis. The tank is decorated is a few pieces of planted driftwood and several ceramic and coconut spawning caves. The water parameters are maintained at 160 - 200 mS conductivity (80 - 100 ppm TDS), pH 6.8 - 7.0, KH 1-3 and a temperature of 78 F. The tank has subdued lighting, with one end being nearly dark. The tanks gets a weekly water change of 25 - 30% at a minimum, and frequently more often and larger in volume. The fish like large water changes, after which they express their best most vibrant colors and outgoing behaviors.
The fish are fed a diet that is heavy in plant material and supplemented with live foods (daphnia, baby brine shrimp, grindal and white worms) and frozen foods (mysis shrimp and chopped krill). They are not fast-growing fish, and three months after getting them both had grown no more than a centimeter in length, but they did fill out and become quite robust. The male established himself as the master of the tank after a month and lost a lot of his shyness, but continues to hide when a person gets close to the glass. The female remains very shy except during courtship. The best way to observe the fish is to turn out the lights in the room, leaving only the tank light on, and watch them from a few feet away from the tank.
When the female ripens she becomes noticeably heavier, especially in the abdomen. Her rosy coloration is more pronounced and darker, and her ventral fins turn black. Her demeanor is more aggressive as well, and she actively seeks out and courts the male. The result is a few beatings from the dominant fish, but her persistence eventually wins him over.
Courtship, once the male agrees to the proposition, involves a lot of dancing and digging. The female turns her body so that her side faces the male, arches her body toward him and shimmies. During water changes I fill the caves with gravel. The pair will systematically excavate all the caves in the tank. When spawning is close they will concentrate their attentions on one specific site, usually a ceramic cave that is located under a piece of driftwood. I removed the other cichlids from the tank during the pair's first spawning. The pair will actively defend the site together and very aggressively attack any fish that comes out of hiding. The male is especially relentless and nearly killed one of the smaller C. sajica. The Ancistrus sp. catfish wisely makes itself very scarce when the P. humilis are preparing to spawn.
Courtship can last for two weeks or more. The female becomes very large with eggs during this period of time. Three or four days before spawning the female's egg tube will drop, indicating that the spawn is near. The female was very secretive in her cave after laying her eggs, and when she does come out it was obvious that she has shed a considerable amount of weight. The male was very attentive to the female who tends the eggs, but spends most of his time positioned in front of the cave on guard duty. Placing a mirror in the tank near the cave generates a very interesting and violent response from the male.
Five or six days after spawning the female will move her brood to a new location. The pair excavates a pit in the gravel under another cave. The larvae were kept in this new location until they became free swimming. I have observed a peculiar behavior that I have not seen from other Pelvicachromis species. The female will barricade herself and the larvae into a coconut cave each evening by piling gravel up in the entrance to the cave from the inside. The gap she leaves was too small for her to get out of without disturbing the pile of gravel. The next morning she will dig her way out making a gap just large enough to get through. She will go into the cave periodically throughout the day, and then barricade herself in again later in the evening. This behavior continues after the fry are free swimming.
The total time from spawning to free swimming is about 10 - 11 days. The fry are very large compared to other Pelvicachromis species. The P. humilis fry were as large on their first day of free swimming as P. taeniatus and P. sp. 'blue fin' are after two weeks free swimming. The parents are both very attentive and share the brood care equally, except at night when it is the female who locks herself and the fry away in a cave.
I try to leave the fry with their parents for at least two weeks, after which I will transfer the entire brood to a ten-gallon grow out tank. The first time I removed a brood from the pair I learned a bit more about the unpredictable aggression of this species. The day after the fry were removed the male gave the female a violent beating. She remained hidden and would not eat at all. I now place a divider in the tank to separate the pair when I remove the fry. The male will make aggressive rushes at the female whenever he catches a glimpse of her through the divider. Two or three days after the divider is put in place the female starts to display for the male, and both dig along the bottom of the divider trying to get through. After two or three days of futile attempts to get past the barrier, the pair will sit quietly next to each other on opposite sides of the grate. I then remove the divider and they behave as a perfectly happy couple. Courtship will usually start again within a week of the divider being removed.
The fry, though large by comparison to other types of Pelvicachromis, are relatively slow growing. I start them in a ten-gallon tank and feed several times a day with a mixture of baby brine shrimp and finely crushed vegetable flake foods. The tank gets a daily 30% - 50% water change. When the fry reach 1 - 1.5 cm (usually about six weeks) I transfer them to a 40-gallon breeder tank to grow. I increase the size and variety of food and continue the frequent large water changes regimen. When the fry are mostly 2 cm long (about 12 weeks) I start feeding mostly vegetable-base flake and pellet foods and wean them off of a lot of baby brine shrimp.
P. humilis is one of my favorite west African cichlids to maintain. I have kept the species a few times over the past ten years, and only recently have seen some success with getting them to reproduce. The keys to success are providing ample space and privacy with the correct water parameters and high water quality. A lot of food helps too. This species is a voracious eater and needs a lot of food to stay in breeding condition. Feeding a lot has a negative affect on water quality, but by keeping a pair in a sparsely populated larger aquarium that gets frequent large water changes having a heavy hand in feeding will not create a water quality problem. I have yet to find a krib that I don't like, and P. humilis is no exception.
© Copyright 2006 Ted Judy, all rights reserved
Judy, Ted. (八月 20, 2006). "Pelvicachromis humilis, A Breeding Account for a Very Large 'Krib'". 慈鯛魚室同好網. 檢索 五月 19, 2013, 來自: http://www.cichlidae.com/article.php?id=378&lang=zh.