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| Procambarus Sp Marmorkrebs |
Procambarus Marmorkrebs
Marbled Crayfish
Procambarus sp. "Marmorkrebs"
Difficulty : Easy
Min. Tank Size : 18.9 Litres (5 US G.)
Size : 2.5-10.2cm (1-4 ")
pH : 7 - 7
Temperature : 18 -25 °C (64.4-77°F)
Water Hardness : 6-6 °d
Availability : Rare
Diet : Omnivore, Pellet Foods, Flake Foods
Life Span : 2-4 years
Alternative Names
Marbled crayfish, Parthenogenetic Crayfish, Procambarus fallax f. virginalis, "Procambarus Marmorkrebs" (sic).
Marmorkrebs, or Marbled Crayfish, are parthenogenetic crayfish that were discovered in the pet trade in Germany in the 1990s. Marmorkrebs are closely related to the "slough crayfish", Procambarus fallax. Procambarus fallax is widely distributed across Florida, but there are no known natural populations of Marmorkrebs. Information provided by one of the original pet traders as to where they got Marmorkrebs was deemed "totally confusing and unreliable"
Marmorkrebs are the only known decapod crustaceans to reproduce by parthenogenesis. All individuals are female, and the offspring are genetically identical to the parent. Because Marmorkrebs are genetically identical, easy to care for, and reproduce at high rates, they are a potential model organism, particularly for studying development. A major drawback, however, is the long generation time (several months) compared to other research organisms.
Marmorkrebs have caused concern as a potential invasive species because only a single individual is needed to establish a new population, and they can reproduce at high rates. They have since been introduced into natural ecosystems on three continents. They have been found in the wild in Germany, Italy, The Netherlands, Madagascar, and Japan, probably through release or escape from aquaria.
Although most reports of Marmorkrebs in the wild in Europe have consisted of only single individuals, an established population has now been documented in Germany, with reports of a second population in another German locale.
The Madagascar population is growing rapidly, causing concern among local authorities.
Although there are no confirmed cases of Marmorkrebs being found in the wild in North America, they are widely distributed among hobbyists in the North American pet trade. Due to concerns about the possible damage caused by the introduction of Marmorkrebs, Missouri added them to its prohibited species list
Marmorkrebs are closely related to Procambarus fallax. A scientific paper (Martin et al. 2010) suggests marbled crayfish be considered an asexual "form" of P. fallax. This is slightly problematic, as "forms" are not often used in scientific names for animals, although the practice is common in plant names.
Marmorkrebs is suggested as a common name because it is distinctive and less likely to be confused with other crayfish with marbled colouration.
Sexing
All marbled crayfish are female and reproduce via parthenogenesis. In related species, males have distinctly different anterior swimmerets than posterior; in females, all swimmerets are very similar.
Tank Compatibility
Larger fish may eat smaller baby crayfish. These crayfish are best in species tanks as they pose a threat to bottom dwelling fish or fish that rest on the substrate during the night. They may also attack other invertebrates.
Diet
Marmorkrebs accept a wide range of food, but may have a slight preference for plant materials. They will eat sleeping or dying fish, dead fish, and meaty sinking pellets designed for crabs or Cichlids. They will also eat softer plants if they are still hungry.
Feeding Regime
Feed twice per day. If pellets get mouldy, remove them. If you see mysterious chew marks on your plastic plants or sponge filters (both have happened to me), then your crayfish are starving. Double the number of times you are feeding them or double the amount for each time, but not both.
Environment Specifics
Provide at least one hiding place for each animal, with 1-2 extra hiding places. They will need these hiding places when they moult, or other crayfish may eat them. A long skinny pot, or length of 1 inch PVC tube (with one end closed) works fine. Crayfish feel safe in very tight space. These creatures are nocturnal and will eat sleeping fish.
Marmorkrebs fare best at room temperature (about 20°C). Although they will grow faster in warmer water, they are also more likely to die.
Behaviour
They tend to dig up rooted plants, but do not use floating plants either, as they will use them to escape the tank. Seal tank thoroughly as they are good climbers and will escape and die. Weight down the top so the crayfish will not push it open. Lower water level 2 inches below black strip at top of aquarium.
Marmorkrebs are often quite mobile and visible around tanks during the day, unless they go into berry. When in berry, they rarely move or feed.
Identification
Brownish appearance with darker brown mottling. Their colour can change depending on diet, occasionally showing slight blues or greens. Many species of Procambarus are extremely similar and difficult to distinguish based on body shape.
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