Self-cloning Marble Crayfish
In February of 2008 I purchased 6 small marble crayfish (Procambarus marmorkrebs) at Grand Valley Aquarium Club. I had never kept crayfish before, only small cherry shrimp. These animals are fascinating to watch move around and eat! They have many little appendages with tiny claws around their mouth area that are constantly picking at debris and the gravel for food. Talk about multitasking! In addition, this crayfish (female) is the only self-cloning crayfish in the world and no males or fertilization is needed to produce babies. Medical research is interested in them since they are genetically identical. They first appeared in the 1990s’ in a shop in Germany and little was known of their origin, although some feel that they originated in the United States. In about 4 months they reached maturity at 2 ½ inches and the 3 that I kept have all produced eggs and babies for me, despite the fact that I kept them in separate tanks. Also, the marble pattern on the body is very attractive and shows up better as they become older. Color can vary according to conditions. It reaches about 4 inches maximum size and is said to live about 2-3 years.
I had much to learn about crayfish. When I first noticed a “dead body” in one of the tanks, I was really upset and wondering what I did wrong! Later, when the crayfish reappeared, I remembered that they outgrow their shells and molt. Feeding them is easy. They eat almost anything: dry food, peas, zucchini, grated beef heart, and they pick at the mulm and plant matter on the tank bottom. They also are known to eat plants. They are probably better off in a tank of their own, as the babies would soon be eaten by most fish. Also, many fish species would probably nibble at their appendages or kill and eat them (think fishing bait). They might be able to catch some slower smaller fish, although I have kept them with danios, tetras, and rasboras and didn’t notice any losses. Some reports claim that they don’t eat their babies and get along well together, although I found that babies would slowly disappear when left with adults, and adults would spar with each other, especially in a small tank. It probably boils down to needing a certain amount of space and hiding places per crayfish.
“Breeding” them is a snap, if you call that breeding! They do require proper food, space, hiding places, and good water conditions. They especially relish blackworms, which seemed to help condition them for breeding. The female lays around 100 black eggs 1 millimeter in diameter which adhere under her tail section. There are small filaments in this area which undulate back and forth to keep them well oxygenated. The female then turns a darker color, eats very little, and remains in hiding. Most of the time she has her tail section folded under to protect the eggs, except when fanning them. It takes about a month for the eggs to hatch, and the fry will scatter about the tank in various hiding places. It seems that the more hiding places there are (rocks, stones, plants, pots, etc.), the better the fry survival. I would remove the female at this time. The fry can be fed by scattering fine dry food over the bottom of the tank. They are excellent bottom cleaners and will find and eat it fairly soon. They are fairly tiny when hatched and will take 1 ½ to 2 months to reach 1 inch long.
The marble crayfish is a very interesting creature, and I recommend it for anyone wanting to try breeding something new and different. Yet we must be aware that with all organisms that we keep in our aquariums (fish, crayfish, shrimp, snails, etc), we must NOT allow any to be used as fishing bait or released into the wild! Exotic species, diseases, and other problems can result in damage to our environment.
Young Self-cloning Marble Crayfish