Why does a crayfish need to molt

The inter-molting stage is the last and the longest stage during which most of the calcium is stored in the cuticle. Basically, it is a period of rest between the end of one molt and the beginning of the next. As the crayfish grows, this phase gradually increases in length. A small growing crayfish will molt more frequently than a larger crayfish.

How can we tell if the crayfish is about to molt? There are different signs that might help you out if you pay attention. Every crayfish has a unique personality. They prefer to eat a certain amount of food or sleep a certain amount of time. All in all, they act a certain way. So, when they are about to molt their behavior will change. For example:. It can be hard to notice but if your crayfish does not have a leg, claw, etc. At first, it looks like a small nub.

However, as the time for molting grows near, it will swell and become more defined. Keep in mind that all of these signs not always occur and sometimes none of them do. It depends on the species, size, age of your crayfish, and their environment.

For example, newly-hatched Procarambus Clarkii will usually molt in a few days. Juvenile crayfish may molt every 7 — 10 days. Adult crayfish molt less frequently, it can be 30 — 40 days or even less. The point is that fully grown crayfish do not grow, they molt only to regenerate lost limbs.

As long as you are providing a good environment and a variety of food, your crayfish will molt regularly. It is very important to know that decreased pH and GH have profound negative effects on crayfish. It affects the inter-molt duration and increases the mortality rate. General Hardness GH is the measurement of the level of dissolved minerals in the water. The power of hydrogen pH also affects the metabolic investment in calcification.

At low pH levels, crayfish exoskeleton becomes too flex and malleable. This is because their shells are composed of calcium carbonate which reacts with acid. As a result, crayfish will have trouble breaking their shells when it is time to molt. It will stress them a lot and can lead to death. Although most crayfish species are pretty tolerant to hardness, it would be better to avoid extreme water parameters anyway.

For example, too hard water may also be a problem for a crayfish. Hard water can make crayfish shell too rigid to break as well. Generally, crayfish will thrive best in water hardness between the ranges of 6 — 14 GH and pH 7. Even though they can tolerate acidic water, it is not good for them in the long run. The problem is that in this phase, crayfish are soft, weak, and cannot fight back. In the wild, they are known to be vulnerable to predation and cannibalism during molting.

In the aquariums, it happens pretty commonly as well. Therefore, if your crayfish is living in a community tank with fish or other crayfish, you will have to provide them with lots and lots of hiding places.

That is why, driftwood, rock, PVC pipes, and decorations are crucial to a successful crayfish tank. Otherwise, they can fall prey not only to other crayfish but even to small fish! Unfortunately, sometimes crayfish can fail at molting they cannot get out of their old shell or cannot even break the shell. They lie on the side and periodically try to bend the shell. In some cases, it may last hours and days. Unfortunately, once the molt starts to go bad, we cannot do anything to help them.

All we can do is wait and hope for the best. The growth process in crayfish demands periodic shedding of the old exoskeleton. Therefore, if you see that your pet has lost some coloration and does not eat much, do not panic, this is a completely normal behavior before molting. Just do not forget to provide them with lots of hiding places in the tank, so they can molt safely. Thank you keep up the great work I greatly appreciate it! Despite efforts to exclude white river crawfish from many farms, both species will thrive under routine culture practices, and they often coexist in production ponds.

No evidence exists of natural hybrids between these two species. Several books provide an excellent overview of the anatomy and biology of these and other crawfish species. Both species, however, possess a number of traits that are usually associated with animals that live in warm waters.

These species are short-lived 2 years or less , have high juvenile survival and can alternate between reproductively active and inactive forms.

Moreover, P. These crawfishes have life cycles that are well-adapted to farm production strategies Figure 1. Mature animals mate in open water where sperm is stored in a special receptacle, after which the female retreats to a burrow to eventually spawn. Females carrying eggs or hatchlings are highly susceptible to predators, because they cannot use their normal tail-flipping escape response.

Crawfish of all ages and sizes, whether mature or immature and male or female, will dig or retreat to burrows to survive periods of dewatering. Crawfish ponds are usually drained during the summer months to allow for planting and growth of vegetation.

Prior to draining, some mature crawfish burrow near the waterline. As the water level drops, additional crawfish burrows appear lower on the levee and are sometimes found on the pond bottom; however, the burrows on the pond floor often contain a high percentage of non-reproductive crawfish, such as males and immature juveniles. Ovarian egg development in mature females is temperature dependent, usually beginning prior to burrowing and reaching completion within the burrow.

Developing eggs within the ovary become rounded, increase in size, and change from a light color to dark as they mature. At maturity, the large black eggs are shed from between the walking legs, are fertilised externally and are then attached to the swimmerets on the underside of the tail with an adhesive substance called glair.

Although crawfish can survive in high humidity within the burrow, some standing water is necessary for successful reproduction. The number of eggs laid varies with female size and condition, but large red swamp or white river crawfish females can have more than eggs. The hatching period depends on temperature and usually takes about 3 weeks. Hatchlings instinctively remain with the female for several weeks after their second molt although they are no longer attached.

It is critical that the female and her young leave the burrow within a reasonable time because little food is available in burrows. When conditions force the crawfish to remain in the burrow, increased mortality can occur. Pond flooding or heavy rainfall is usually necessary to encourage female crawfish to emerge from their burrows.

Females emerge with their young or sometimes with eggs attached to their tails Figure 3 , and advanced hatchlings are quickly separated from their mother as she moves about in the open water.

Because reproduction is somewhat synchronised in pond-reared crawfish, ponds are routinely flooded in autumn to coincide with the main period of reproduction. White river crawfish are autumn and winter spawners, but red swamp craw fish reproduction may occur at any time. Extended reproduction and differential growth typically result in a population of mixed sizes in most ponds. As with all crustaceans, a crawfish must molt or shed its hard exoskeleton to increase in size.

Frequent molting and rapid growth occur in production ponds when conditions are suitable. Growth rate is affected by a number of variables, including water temperature, population density, oxygen levels, food quality and quantity, and to a lesser extent by genetic influences. Harvest size is typically reached 3 to 5 months after hatching for fall recruits, but it can be attained in as little as 7 to 9 weeks under optimum conditions.

When males and females molt to a reproductively active stage, growth ceases. Sexually mature individuals exhibit distinct characteristics, including darker coloration, enlarged claws, and hardened sexual structures.

Mature males also develop prominent hooks at the base of the third and fourth pair of walking legs. The appearance of mature crawfish in the population usually increases as temperatures rise during late spring.

They tend to release their shell each fifteen to twenty five days in proper environments and conditions. The total time depends on their size too. As in smaller crayfish take less time than the bigger ones to molt.

Generally, it is seen that crayfishes take 24 hours to 3 to 4 days to complete the whole molting process. The younger crayfish shed their shell every seven to ten days where the adult ones take more time, around thirty to forty days. As long as they are getting the proper environment, they will keep molting at their regular speed. Basically, the whole process takes some time, but the disposal of the old hard shell is done in a minute or two. The rejuvenation process starts as soon as they develop the previous hard shell that they are about to shed with tissue.

When it is filled, another delicate skin structures underneath the hard shell in anticipation of shedding. When they are shedding, the hard external shell is disposed of. The arising delicate crayfish can now grow in size. The delicate bare skin then becomes solid at one point with calcium and frames another hard shell. During this short time frame, the delicate crayfish are also commercially gathered for harvesting. Crawfish shedding is generally hormone controlled.

The extension in crawfish size during shedding as well as the time duration between sheds can change altogether. The whole procedure can be affected by several factors, for instance, water temperature and quality, food quality, oxygen levels in the water. If the conditions are favorable, crawfish tend to grow up to fifteen percent long and forty percent in weight in a long shed. Actually, the shedding is all about growing because the hard shell act as a barrier and it needs to be removed occasionally.

Crayfish Dude enjoys writing about crayfish, fish tanks, and other aspects of the aquarium world. When he's not writing, he can be found at the gym or searching for nerdy documentaries on Amazon Prime.

My crayfish is in a tank with very little enclosure. This morning, he was being VERY sluggish and tiny bubbles were forming on top of his shell, so I took out his companion beta fish, and covered my tank with a heavy blanket, so no light could get in.

I have had him for about 2 months, and I was just wondering if he was about to molt, and if he was, was I doing the right thing? I found HER in fresh water.. And she is also about to molt. I think you did the right thing. Remember me Log in. Lost your password? How to Tell if Your Crayfish is About to Molt The first thing I noticed about my electric blue crayfish that made me think something was going on was when he seemed to hide all day long under the hideout in my fish tank.