Crayfish (aka Freshwater Lobster)

Originally Posted by ivor

bros any tips on breeding the common red or blue?? cheers

I've been rearing some common blues for a while now and they seem to eat everything, worms, dead fishes and even bread. So far I have not seen my blues attack other fishes, and I'm keeping them in a tank with tilapias, mini puffer, holland rams, catfish, solefish, gobies, shrimps and helicoptor/plecos with no problem.

Very hardy, very hard to go wrong I think.

[Gus]

Gd idea i also want to know about the red & the zebra.

maybe someone can provide some information abt it

Originally Posted by ivor

bros any tips on breeding the common red or blue?? cheers

[Gus]

Shell Disease is one of the more common diseases effecting crayfish. No doubt most of you have seen this and many of you do not know how to treat it. Knowing how to treat shell disease, requires you know a little about what this little nasty is that is rotting away your crayfish's shell.

Other names shell disease goes by is, box burnt disease, shell rot , brown spot, black spot, burn spot or rust disease. The cause is primarily an opportunistic bacteria that will invade some small injury on the crayfish. You will have seen a small rusty spot on the end of an antenna that has been nipped off or broken. This is the start though quite often with a small injury like that it will not spread any further and is removed with the next moult.

With larger injuries the crayfish's armor is breached and gives the opportunity for microorganisms like bacteria, fungi, or protozoans to start their invasion. At this point these nasties basically eat into the shell (chitin) and here in lays the problem for the aquarium enthusiast and aquaculturist alike. What happens is the bacteria eat through the outer three layers of the hard exoskeleton and start into the nice soft layer. This soft layer is the beginning of the next moult and then the outer and inner are "fused" together, which can prevent the crayfish from moulting. No moult, no growth, no grow = death. This is where the infected crayfish will get "stuck" in a moult.

There are other causes of this disease and they include, the stress of capture, high temperatures along with high suspended nutrient, over crowding and the biggest is poor water quality. Crayfish are very tolerant of poor water quality but the biggest risk is poor substrate. When your excess foods get trapped in your substrate it becomes anaerobic (no oxygen), which encourages these nasty little gram negative bacteria and your crayfish sits in them all day and night. Hint, clear your substrate regularly.

Below I have provided you with pictures of a Cherax destructor with advance lesions. Note the brown indents into the shell of the crayfish. These will start out as little brown to black spots no bigger than a pin head.

[Gus]

The good news is there are quite a few ways to treat this shell disease, but the first thing you must to is check your water quality. If you don't have a reasonable quality test kit for ammonia, nitrite and nitrate I strongly suggest you get one. You can treat this disease and then put the crayfish back in the same water and have the same issue again and again.

Lets just dispel a few myths while we are getting down to it:
Is it contagious? The answer, from what I have seen is no, even if another crayfish eats the dead one. Remember it is a bacteria infecting the shell of the crayfish, it does not jump from host to host it is not a pathogen. This also means it can not be transfered to fish and other crustaceans sharing the same tank.

I have lots of calcium carbonate, will this prevent shell disease? The answer is not at all, as the opportunistic bacteria are just that, opportunistic and regardless if your calcium hardness is high and your crayfish is injured or stressed, it will get shell disease. To what extend depends on you and your water management.

Can I treat shell disease with Melafix? For very minor injuries like the crayfish antenna in my earlier example, yes but it will not cure it. Melafix is an extremely mild anti-bacterial treatment that borders on useless which will only minimize the damage caused by the bacteria until the crayfish next moults. In severe cases, such as the photos above Melafix will do absolutely nothing at all.

Will water changes help at all? Nope, you can not dilute bacteria. That said, you may need water changes to correct your water quality should the testing recommended earlier, be less than desirable. Water chemistry changes will further stress the crayfish, if stress is the primary cause for the shell disease. First test your water in the tank and then decide if a water change is needed from those results.

Is an itchy bum a sign of worms? Yep it more than likely is.

Now after all that, lets get on with the cure: There are none.... Just jokes

There are several methods but I will give you the easiest one. Dip your crayfish in sea water for ten minutes every three days. That was easy huh? What I mean is the following:

Grab a set of scales and measure out 35grams of salt
If you don't have micro scales a good teaspoon is around 4.7grams, so 7 nice teaspoons will do.
I don't mind what salt you use, personally I prefer pool salt.
Throw that in 250ml of boiling water and stir in until dissolved.
Then take 750ml of water from your crayfish mates tank put it in a 4litre ice cream container or something similar with high sides.
Add the dissolved salt solution to it and stir again.
Drop an airstone to keep the water nice an aerated.
Set up an alarm clock to 10 in the future.
Drop your crayfish in and make sure it can not escape.
Go do some maintenance on the tank.
Come back and remove when the alarm goes off.
Repeat every 3 days as needed until next moult or lesions are "bleached out".

[Gus]

This is a few comment by some member from crayfish mate forum on almond leaves (ketapan leave) which can help in Shell Disease And Ugly Brown Spots.

1) Yeah these leaves are great. If you can't get the almond leaves Oak leaves do work great as well. I have even seen in some cases where it helped with Shell Rot.

2) use oak leaves for my shrimp ...Stand them in tank water on the window sill for 10 days to get most of the tanin out then drop them in at about 3-4 day intervals.
The Tanin that is still pressent is a natural disinfectant ( trees actualy use it as such ,flooding their systems when other walls of deffence have been breached) so is good for any fish spawning having a natural fungicide in the water .but the bacteria which developes and the algea which forms is great food for the shrimp larvea .I have also dropped leaves in with my crays some times as a distraction so they wound eat the java moss I keep putting in LoL they love it ! but they do go for the leaves .Only negative I can see is your pH will need monitoring as it will fall.

[Gus]

Feeding Crayfish

Crayfish are preferably detrivores (eat decaying plant/vegetable matter) though are still opportunistic omnivores, which means that given the opportunity the crayfish will eat just about anything given to it, healthy or otherwise. Because of this feeding behavior it is important that you, the provider for the crayfish, supply the right types of food for your little guys health and happiness.

They are also considered Benthic feeders, meaning they eat and dwell on the bottom of the tank. This means that you will, no doubt, have to be sure your crayfish mate can reach the feed you are giving it. A sinking feed is always helpful.

How much to Feed?
This will vary from tank to tank. The most important thing to keep in mind is preventing your water from getting "ugly" as it will do more damage to your crayfish than not feeding it. Crayfish can and will go for weeks without eating, especially if the water temp is at the lower end of their scale. So keep an eye on the food if it is left over. Quite often I will not feed a tank for a week to let it be cleaned up by the crayfish.

In general crayfish will eat roughly 1% of their body weight every two days or 0.5% every day. If you know how much your crayfish weighs then you can work out how much to feed it. That gets a bit technical really, but useful if you are into that type of math. Feeding for each crayfish in the tank, one pellet, or piece of feed the size of a pea every second day will keep them happy.

Will my Crayfish Mate eat my other wetpets?
Undoubtedly, your crayfish will eat what ever it can find. Many members here keep community tanks with no fatalities and others with somewhat less than desirable results. One of the keys to preventing your crayfish from munching on your other mates, is to keep it well fed. As with any omnivores, they will eat anything if they are hungry enough. Wouldn't you?

Your Crayfish will Eat Plants!
They will definitely uproot and mostly destroy any plants that you have in the tank. To prevent this from happening, it is best to have the crayfish in the tank and settled before introducing plants. Personally, I have fully planted tanks with many different species and aside from a little "clipping" now and then, the plants are left where they are. If a crayfish is introduced to a fully planted aquarium, they will rummage around and move all your substrate until they have it just how they want it.

Feeding Veggies that Float
If you are feeding vegetables, which are great, the downside is they tend to float. In this case you can use a plastic clothes peg from the clothes line and attach a small suction cup to it. Clip your fresh veggies to it and stick it on the side of the tank near the bottom. Or simply stuff the veggies in a very small, clean glass jar (baby food) and drop it in the tank without a lid. Great for going away for a week or so.

When feeding veggies be sure to wash them properly to prevent poisoning your crayfish with any "anti life" residue left on them. Always good just o give them a quick 3 minute soak in boiled water before putting them in the tank. Hard veggies like carrot, potatoe and pumpkin tend to grow fungus in the tank before the crayfish will touch it, by then it will be floating and "hairy", so the blanching helps soften them up for chewing.

What not to Feed your Crayfish Mate
Quite often we hear great stories of crayfish munching on hotdogs and chilli beans. As interesting and amusing as these stories are, it is best to steer away from processed foods. Any whole shrimp based feeds are not advisable as they can still carry WSSV (White Spot Syndrome Virus)

Below are some feeds used by the members here on Crayfishmates.com

Commercial Fish/Crustacean and other Feeds
Feeds from your local fish shop generally do the job and most commonly used. You may need to add the odd veggie once a week to be sure good vitamins are available (especially A).

algae tabs
fish food flakes
krill
grounded dry fish food
rabbit pellets (most pellets like chicken work well)
Shrimp pellets
tropical fish flake
ssinking fish food
HBH Crab & Lobster Bites
sinking cichlid pellets
algae wafers
Fresh and Frozen Fruits
All fruits are great, though it is important to keep an eye on the amount of acidic fruits, such as oranges or anything citrus as these will lower the pH. of your water and we all know what happens with sudden drops.

apple
Banana
orange
red apples
fresh strawberries
green grapes
Fresh and Frozen Vegetables/plants
Fresh veggies and plant are the best of any feed and rarely causes water issues from overfeeding. When you are planing to have plants in your aquarium, the crayfish are planing on you not having any. Only small pieces are needed and often a veggie clip (DIY forum) to hold them down.

cucumber
frozen pea
garlic
organic zuchini (spoiled crayfish, any zuchini/squash will do)
spinach
spirulina
Plants
duckweed
certain algae
string bean (any green beans are great)
frozen carrots
frozen peas
frozen sweetcorn
moss ball
Fish and other Animal Meats
Meats like steak and processed meat are best not used and of so in very small amounts because they will cause water quality issues quite quickly. Any seafood, very fresh is possibly the second best feed to use but again in small amounts.
fat juicy wax worms (black, blood, earth or any - just watch the fat content)

lean ham (limit the use of processed meats)
live earthworms
mussel
frozen blood worm
prawn
snails
some fish (any fresh fish at all)
squid
egg shells
fresh chicken
leftover turkey
steak
Mealworms (Tenebrio molitor larvae)

[Gus]

That is a great question. The first things to stay away from is animal proteins in your water from the like of beef etc only from a water quality point of view. Fish is a better form of animal protein in this case and live/very fresh is the best option.

The second thing to watch for is insecticides on the vegetables you are feeding your crayfish, they will kill them very very quickly. Crayfish are not much different to other insect crustaceans and are just as sensitive to insecticides. I would not be surprised if this was the cause of a majority of "mysterious" deaths in aquariums.

The biggest thing to watch when feeding, or doing anything to your crayfish is copper. That said, best to not over feed foods that are high in coper as it will build up in their system and kill them. Foods like the following...

Shrimp
avocados
grapes
almonds
peanuts
mushrooms
legumes
brazils
cashews
poppy seeds
sunflower
chickpeas
liver

The above list is only to say do not over feed on these items, not to say do not feed them at all. Just avoid where you can. The funny thing about crayfish and other crustaceans, like shrimp, is they are naturally very high in copper so feeding your crayfish other crayfish constantly would no doubt actually harm them.

Lettuce is also used as a natural insecticide. When boiled, cooled and the water left used in a sprayer, will kill flies, so possibly one to avoid.

If anyone has any other stuff to add by all means...

[Gus]

Moulting Crayfish

Moulting (ecdysis) in crayfish/crawfish is a neccessary part of the growth and development of any species. The entire moult process consists of five stages, which include pre-moult, inter-moult and post-moult as a continuous process.

The general process of a moult is from the pre-moult when the shell (exoskeleton) is hard and the crayfish feeds normally and is very active. During this stage a nice new shell is forming underneath the old one and you may be able to notice a slight darkening of the color in the hard shell. At this time they begin to absorb the calcium deposits in the old shell which "thins out" the old shell. Towards the end of this pre moult stage your crayfish will become very shy and seek shelter if it is available and will not feed.

Inter-moult stage is the quickest and in normal conditions completed in a maximum of 10 minutes. This is when they flick out of their old shell and are all very soft and spongy. Now is a good time for the crayfish to have somewhere to hide. During this soft phase the crayfish will swell right up and commonly grow in size 15% to 40% of their original size.

Then comes the hardening stage or post-moult. Now the calcium stored held within two little white (chalky) gastroliths and in the new shell to some degree. These little white stones is where majority of the calcium in the body is stored from the moulting process. Then once those have been absorbed into the new exoskeleton, the crawfish continues to absorb calcium from the water. This is where it is important to have a high water hardness.

Can i aid moulting with additives?
Yes you can. Generally speaking, if your water conditions are ideal then there is no need to assist the crayfish in the moulting process. It is a common mistake to over feed a tank when a crayfish is in the pre-moult stage which does spike the nasties in the water. Quite often it is ideal to make sure you have plenty of oxygen getting into the water column and if your water hardness (GH) does not contain at lease 150ppm of calcium and temporary supplement of calcium bicarbonate (baking soda) will assist a crayfish struggling with a moult. A minimum dose of 20grams per liter will do the job without any negative effects.

How can i protect my cray after moult?
It is very important to provide your crayfish with somewhere to hide at all times. Yes, we all like to see our crayfish in the tank but simple hides like 4inch pvc facing the front of the tank will assist in providing a space where the crayfish feels safe to moult and grow. With out this the crawfish will still attempt the moult and 90% of the time it will be successful but there will be times (especially when older) the added stress of no where to hide will kill them.

Should i feed my cray after a moult, if not how long should i leave it?
The whole moulting process can take 15 days to complete with a week each side for pre-moult and post-moult. Your crayfish will need to regain its energy reserves as quickly as possible after a moult and will be quite aggressive 5 days after a moult. Best to continue your normal feeding if it is a community tank. If it is a single crayfish in a tank, then a 5 to 7 day wait until you resume normal feeding is best to be sure your water quality remain consistently high.

Can i force a moult from my cray and how?
A crayfish normal moulting cycle is brought on by quite a few technical responses to water quality, light, feed and environmental changes. That said, the general moulting triggers for crawfish are a pH. change in the water, and/or a temperature change, and/or a photo period (light) change.

Majority of these changes occur during natural seasonal changes. The days getting longer, the water temp getting warmer and with those two changes there is usually a sudden drop in pH which then swings back up. So to manipulate moulting cycles you would need to make these changes to reflect the natural growth seasons for the species you have. A note of caution has to be mentioned as you are dealing with the actual growth and development of the crayfish and mistakes can and will kill your pet.

My crayfish lost a leg, pincher or part of it’s antennae, will it grow back?
The loss of limbs is very common in crayfish, especially when they are in a community tank with fish. Fish see them moving about and nip the ends off them. Other times a crayfish will lose a leg or two and even their claws, during times of stress and especially during a moult.

When the loss occurs during a moult it is often from "getting stuck" in the moulting process. This happens to a few crayfish in their life time. Sometimes it is just one or two limbs or antenna and other times it is their whole shell.

Crayfish or Crawfish have an ability that we humans do not have and that is they can and do grow back limbs. This happens over successive moults. This is to say, it will take up to three moults to fully recover the lost limb.

Do I leave the old discarded shell in or need to remove it from the tank?
Removing the discarded shell really depends on the calcium hardness level in your water and if you have multiple, which most people do, crayfish in one tank.

In a community tank, the discarded shell is very very attractive to other crayfish and mildly interesting to fish. It is always a good idea to leave the moulted exoskeleton in a tank with other crayfish but not as important with other fish. The reason for leaving the old shell in when other crayfish are present, is it acts as a decoy for the freshly moult and very soft crayfish, giving it time to find a protected location in the tank to harden up. The other crayfish are usually too busy to worry or attack the "moulter". This only slightly works for fish as they are not that interested in the discarded shell.

In a tank with just the single crayfish, you can remove or leave it there depending on the calcium hardness (GH) of the water. If your water hardness is lower than 150ppm, personally I would leave it there just in case the crayfish is looking for another source of calcium carbonate that it can not absorb from the water to harden up its new shell. If your hardness is above the 150ppm, it is safe to remove the discarded exoskeleton. Just watch how long it takes to eat the shell and remove any remains after a week.

Will my crayfish regain it’s color it had before the molt?
Most crayfish will become a much lighter color with each moult it has in an aquarium. The simple reason for this is the water quality in a fish tank is much higher than that of a pond or creek and there are a great deal less suspended minerals which make the crayfish darker. In the practical sense your crayfish will go a lighter color after a moult and as it absorbs more calcium and minerals from the water it will become darker.

Will my cray fall victim to the others during the molting process?
Yes and no. Canabalism is more likely if the other crays are hungry or especially lacking in calcium, which is very common in aquariums. The best way to prevent injury or death to your newly moulted crayfish is to provide it with somewhere safe to moult and recover and keep the other occupants well fed. Dosing the tank with calcium helps "disguise" there is another crayfish moulting in the tank. Best methods are well fed, not over crowded and places to hide and change cloths.

How often does a cray molt?
How long is a piece of string? From a fry they usually take at least 11 moults to reach adult hood. This does vary slightly for each species but generally speaking a good number. For the most common aquarium species around the world at 11 moults they will be approximately 12 months old. From that age they moult roughly at 15 months, then 19 months then 24 months then 30 months and then 40 odd months. How often they moult is really dependent on their environment and feed.

What are the desired water parameters to help my cray molt successfully?
General conditions for the most common aquarium crayfish species is 150ppm calcium hardness, no nitrogens at all, water temp optimum for breeding the species and plenty of oxygen (5 to 7ppm)

[Gus]

There are several methods to cure the Shell Disease and this is the easiest one.

Dip your crayfish in sea water for ten minutes every three days.

What I mean is the following:

1. Grab a set of scales and measure out 35grams of salt
2. If you don't have micro scales a good teaspoon is around 4.7grams, so 7 nice teaspoons will do.
3. I don't mind what salt you use, personally I prefer pool salt.
4. Throw that in 250ml of boiling water and stir in until dissolved.
5. Then take 750ml of water from your crayfish mates tank put it in a 4litre ice cream container or something similar with high sides.
6. Add the dissolved salt solution to it and stir again.
7. Drop an airstone to keep the water nice an aerated.
8. Set up an alarm clock to 10 in the future.
9. Drop your crayfish in and make sure it can not escape.
10. Go do some maintenance on the tank.
11. Come back and remove when the alarm goes off.
12. Repeat every 3 days as needed until next moult or lesions are "bleached out".

Originally Posted by Gus

Shell Disease is one of the more common diseases effecting crayfish. No doubt most of you have seen this and many of you do not know how to treat it. Knowing how to treat shell disease, requires you know a little about what this little nasty is that is rotting away your crayfish's shell.

Other names shell disease goes by is, box burnt disease, shell rot , brown spot, black spot, burn spot or rust disease. The cause is primarily an opportunistic bacteria that will invade some small injury on the crayfish. You will have seen a small rusty spot on the end of an antenna that has been nipped off or broken. This is the start though quite often with a small injury like that it will not spread any further and is removed with the next moult.

With larger injuries the crayfish's armor is breached and gives the opportunity for microorganisms like bacteria, fungi, or protozoans to start their invasion. At this point these nasties basically eat into the shell (chitin) and here in lays the problem for the aquarium enthusiast and aquaculturist alike. What happens is the bacteria eat through the outer three layers of the hard exoskeleton and start into the nice soft layer. This soft layer is the beginning of the next moult and then the outer and inner are "fused" together, which can prevent the crayfish from moulting. No moult, no growth, no grow = death. This is where the infected crayfish will get "stuck" in a moult.

There are other causes of this disease and they include, the stress of capture, high temperatures along with high suspended nutrient, over crowding and the biggest is poor water quality. Crayfish are very tolerant of poor water quality but the biggest risk is poor substrate. When your excess foods get trapped in your substrate it becomes anaerobic (no oxygen), which encourages these nasty little gram negative bacteria and your crayfish sits in them all day and night. Hint, clear your substrate regularly.

Below I have provided you with pictures of a Cherax destructor with advance lesions. Note the brown indents into the shell of the crayfish. These will start out as little brown to black spots no bigger than a pin head.

[Gus]

Things Not to Feed to Crayfish
That is a great question. The first things to stay away from is animal proteins in your water from the like of beef etc only from a water quality point of view. Fish is a better form of animal protein in this case and live/very fresh is the best option.

The second thing to watch for is insecticides on the vegetables you are feeding your crayfish, they will kill them very very quickly. Crayfish are not much different to other insect crustaceans and are just as sensitive to insecticides. I would not be surprised if this was the cause of a majority of "mysterious" deaths in aquariums.

The biggest thing to watch when feeding, or doing anything to your crayfish is copper. That said, best to not over feed foods that are high in coper as it will build up in their system and kill them. Foods like the following...

• Shrimp
• avocados
• grapes
• almonds
• peanuts
• mushrooms
• legumes
• brazils
• cashews
• poppy seeds
• sunflower
• chickpeas
• liver

The above list is only to say do not over feed on these items, not to say do not feed them at all. Just avoid where you can. The funny thing about crayfish and other crustaceans, like shrimp, is they are naturally very high in copper so feeding your crayfish other crayfish constantly would no doubt actually harm them.

Lettuce is also used as a natural insecticide. When boiled, cooled and the water left used in a sprayer, will kill flies, so possibly one to avoid.

If anyone has any other stuff to add by all means...