วันจันทร์ที่ 21 ตุลาคม พ.ศ. 2556

Fish Data : Demanson's Cichlid


 The Demasoni Cichlid, Pseudotropheus demasoni, is a relatively rare cichlid, which originates from a specific rocky point called Pombo Rocks, within the waters of Lake Malawi located in Tanzania, Africa. The male of this species has dark blue or black vertical stripes with alternating lighter stripes of light blue to white. The male Demasoni Cichlid also displays the typical spots on the anal fin, and is considerably larger than the female. The female of this species is not as brilliantly colored, and lacks the spots on the anal fin.

 The Demasoni Cichlid is a relatively new addition to the aquarium hobby, as it was introduced into the hobby trade around the mid 1990's. Its bright coloration, sharp lines of color contrast and relatively peaceful demenior made it a very popular species almost overnight. Demasoni Cichlids are a dwarf species that typically grow to around 5", which makes them suitable for smaller African Cichlid aquariums of 55 gallons or more. In its natural habitat, the Demasoni Cichlid is found in large schools that swim near and amongst rocky areas that provide them protection from larger species and plenty of plants and algae on which to graze. In the home aquarium, the Demasoni Cichlid is an ideal specimen that will aggressively swim about rock formations in their unique quick elusive manner that makes them a joy to watch.

   This is a dwarf Mbuna that only reaches about 2 1/2 to 3 inches (6.4 to 7.6 cm) in length. It is a pretty cichlid that has a very inquisitive nature with lots of personality and spunk. It is an interesting fish to watch as it follows the contours of the rocks, swimming along at odd angles to the point of being upside down. The body pattern consists of crisp alternating stripes that are dark blue (almost black) and light blue. On the dorsal fin the stripes angle back with the lighter ones being thinner than the dark ones. The upper and lower fins, as well as the tail fin, are edge in a light blue.

    The Demanson's Cichlid is sometimes confused with the Pseudotropheus minutus, being similar in size and color. Differences are that on the P. minutus, the lines stop before the tail fin and are less distinct. Also the Demanson's Cichlid males have an egg spot.

   This is zebra-type cichlid is a member of a group called Mbunas. There are 13 genera full of very active and aggressive personalities of Mbuna cichlids. The name Mbuna comes from the Tonga people of Malawi and means "rockfish" or "rock-dwelling". This name aptly describes the environment these fish live in as opposed to being open water swimmers like the Utaka cichlids and other "haps".
This is a great fish for both the intermediate and experienced cichlid keeper. Although its a lively little cichlid, it is moderate to hard to care for and is very aggressive. This is not a community tank specimen to be housed with fish other than cichlids. Because of its small size, it can be housed in a bit smaller tank than what is typical for Mbuna, but of course bigger is better.

   No matter what size the aquarium is they should to be kept in a group of twelve or more to help disperse aggressive behavior. This helps keeps the dominant male from exhausting females and others as a result of constant chasing, by spreading the "love" out. Make sure the aquarium has ample rock formations that provide lots of hiding places, as this will also help ward off brutal aggression between them. Piles of rocks can be arranged to create multiple caves and passageways.
They can also be kept in a large aquarium of mixed Mbuna species, but again there must be plenty of hiding places. Success is dependent on the aquarists willingness to do frequent water changes, have sufficient numbers and hiding places, and provide appropriate tank mates. The Mbuna's have been bred in captivity and with all the different hybrids that have been formed, there is no way to tell exactly what you are getting unless it is from a reputable dealer. Try and keep the different species blood lines pure.

    The Demanson's Cichlid is an omnivore that needs mainly herbivorous foods. Their diet should consist of vegetable matter. An all purpose, high quality cichlid formula can be used as a basic diet. Including vegetable supplements to their diet will help with overall health. This food has fiber which keeps their intestinal tract disease free.

   It is always better to feed them small amounts several times a day instead of one large feeding. This keeps the water quality higher for a longer period of time. Of course, all fish benefit from added vitamins and supplements to their foods. It would not be wise to house this fish with other genus of cichlids that eat beef heart or other mammal meat, as these foods will cause intestinal infections and death.

 Aquarium Setup

   The streams that flow into Lake Malawi have a high mineral content. This along with evaporation has resulted in alkaline water that is highly mineralized. Lake Malawi is known for its clarity and stability as far as pH and other water chemistries. It is easy to see why it is important to watch tank parameters with all Lake Malawi fish.

   Rift lake cichlids need hard alkaline water but are not found in brackish waters. Salt is sometimes used as a buffering agent to increase the water's carbonate hardness. This cichlid has some salt tolerance so can be kept in slightly brackish water conditions. However it not suited to a full brackish water tank. It can tolerate a salinity that is about 10% of a normal saltwater tank, a specific gravity of less than 1.0002.

    A 40 gallon tank will work for a single fish, but 100 gallons or more will be needed for a group or a mixed mbuna tank. The Demanson's Cichlid should always be house in numbers of 12 or more to help alleviate extreme aggression by the dominant male towards females or others. They do fine in either freshwater or brackish freshwater but need good water movement along with very strong and efficient filtration.

   Sand is the preferred substrate, but some aquarists have also used crushed coral or a mix of gravel and crushed coral. A substrate of crushed coral or sand used for salt water tanks can help keep the pH up. They also tend to dissolves easier than salts. Keeping a higher pH however, means that ammonia is more lethal, so regular water changes are a must for these fish.
They need caves and rocks to explore as they are very curious little fish. Having several niches will help them have their own territory, which is also better for the subdominant females and males. Moving rocks around every so often may also help with an overly aggressive fish.
  • Minimum Tank Size: 40 gal (151 L) - A minimum of 40 gallons for a single fish, with 100 gallons or more for a group.
  • Suitable for Nano Tank: No
  • Substrate Type: Sand/Gravel Mix
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 75.0 to 82.0° F (23.9 to 27.8° C)
  • Range ph: 7.6-8.6
  • Hardness Range: 10 - 18 dGH
  • Brackish: Sometimes - Salt is not found in their natural environment, but they do have a slight tolerance, keep levels below 10% - a specific gravity of less than 1.0002.
  • Water Movement: Moderate
  • Water Region: Middle - These fish will swim in the middle areas of the aquarium.
Social Behaviors

   The Demanson's Cichlid is aggressive and is not considered to be a community fish. In fact, it should only be housed with other aggressive Mbunas. Only keep them in a community Mbuna designed tank with lots of rock structures. They are very territorial, even a 1/2 inch male will chase away a medium size fish from his territory.

    Do not house them with ANY fish that has the same hue or other fish that have bars, including a yellow with dark bars. Do not house with similarly colored species, especially species like the Dogtooth Cichlid Cynotilapia afra or Kenyi Cichlid Maylandia lombardoi. You can house them with a yellow Mbuna that does not have bars and they will be fine. Some examples of appropriate tank mates are a yellow species of Electric Yellow Labidochromis caeruleus, the Red Zebra Maylandia estherae, and the Cobalt Zebra Maylandia callainos.
This fish is best kept in a group of 12 or more. The male to female ratio can vary, but there should be more than one male. You may need to experiment with your fish's temperament to determine how many males you can keep. In the wild they live in large groups, but the reason for the large grouping in a captive environment is that this larger number will prevent the dominant male from focusing his aggression on just a few fish, thus leading to their death. With a large number, the subdominant females and males are 'lost in the crowd'. If the numbers are too low, such as 5 or 6, a male will systematically kill the others until he is alone. There will be a dominant male in the group, and once he has established himself, the other Demanson's Cichlids will avoid fighting with him. If you cannot provide the needed room, it is best to leave this one at the store.
  • Temperament: Aggressive - Should only be housed with other aggressive Mbunas.
  • Compatible with:
    • Same species - conspecifics: Yes - They are best kept in a group of 12 or more. The male to female ratio can vary, but there should be more than one male.
    • Peaceful fish (): Threat
    • Semi-Aggressive (): Monitor
    • Aggressive (): Safe
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Threat
    • Shrimps, Crabs, Snails: Threat - is aggressive
    • Plants: Monitor
Sex: Sexual differences 

   For the first couple of months juveniles of both sexes are the same size and shape. This makes sexing next to impossible unless you vent them. As they get older, the males will develop elongated ventral fins and an egg spot.

Breeding / Reproduction

   The Demanson's Cichlid has been bred in captivity. This cichlid is a mouthbrooder that needs to be in numbers of 12 or more. At one inch a female will start to brood but the number of fry will be low. Once the dominant male decides to breed, he will become severely aggressive and pummel to death any other male in the tank if the tank is too small, or if there is a lack of hiding places for the other fish. Like other mbunas the males coloring will change. He will shake and circle the female, moving her to a flat rock in his territory, then the breeding begins.

   The female will lay between 5 - 15 eggs and then immediately takes them into her mouth. The male will then flare out his anal fin which has an 'egg spot' patterning. The female mistakes the patterning for her own eggs and tries to take them in her mouth as well. This stimulates the male to discharge sperm (milt cloud) and the female inhales the cloud of 'milt', thus fertilizing the eggs in her mouth. In seven days, at about 80° F, the eggs hatch. The fry are free swimming in another two weeks.
Feed the fry crushed flake, Cyclopeeze and freshly hatched artemia. Even the fry are aggressive and will pick on each other. Older siblings don't think twice about eating the newborns if they can fit them in their mouth. See the description of how cichlids breed in Breeding Freshwater Fish: Cichlids.
  • Ease of Breeding: Easy
   Fish Diseases

  Malawi bloat is a typical disease for the Demanson's Cichlid, especially if their dietary needs are not met with quality foods. They are susceptible to typical fish ailments, especially if water is stale and of poor quality and oxygenation. One common problem is Ich. It can be treated with the elevation of the tank temperature to 86° F (30° C) for 3 days. If that does not cure the Ich, then the fish needs to be treated with copper (remove any water conditioners). Several copper based fish medications are available for Ich. Copper use must be kept within the proper levels, so be sure to follow the manufacturers suggestions. A copper test also can be used to keep the proper levels. You can also combine increasing the temperature with an Ich medication treatment.

   As with most fish they are susceptible to skin flukes and other parasitic infestations (protozoa, worms, etc.), fungal infections, and bacterial infections. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference

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