breeding crayfish

[weedywhaoo]

Thank you Crayfish for the information. I had 2 females and 2 males in a tank. I have removed 3 crayfishes, so now its only the pregnant crayfish left there. I will keep the mother there and not put her in a special cage to protect the eggs.

The first time the other female was pregnant I made the mistake of moving her to another tank, only a few craylings survived the transport. I have also put in some dried grass and will se if that would lead to some planktons in the water. I am curious of the powder you used to create plankton. Is is possible to buy that here in Thailand?

During the last six months I have searched the internet for information about red claws. I now have many files, and research reports about this subject. If anybody is interested, I would happily share these files with you.

I have never uploaded a file here but I will try with one file that is worth reading.

13-007.pdf

[crayfish]

Hi Weedywhaoo... Last week I bought a small bag of plankton( about 6 tablespoons ) from one of three pet shops in town. For this I paid 100 baht. I have just bought another 100 baht bag and have ordered a full tin, I have to wait until next week for it to arrive. I'm not sure how many grams it is but the tin is the size of a one litre container. At 1300 baht it seems expensive but there is enough to feed thousands of crays. Try your local pet shops, the Thai name for plankton is plankton with an emphisis on the ton. If you have any problems I can supply you with some of this after next week.

Please feel free to attach any files as you like concerning crayfish, especially redclaws. The one you attached I read several months ago and is very informative. James Cook University have done several surveys on redclaws and produced some good documents. I really want some more info on Tolga redclaws but the government Aquaculture department in Aussie don't seem to want to give out too much info on them.

Regarding marketing the redclaws, I feel confident I can open the market without too much trouble. If I tried to sell them as they look now ( multi-coloured) people would wonder what they are. But once they are dropped in boiling water they turn pink , the same as a normal prawn. Just tell everyone they are giant prawns.

[weedywhaoo]

Thanks for the tip about plankton. I will try some petshops here in Phuket and see if they have it.

Crayfish, may I ask where you live?

Here are some more red claw files. Some of it is some boring reading but the In tech advances file has very nice pictures of egg development.

CRAWPM.pdf

crayfishtechD.pdf

50 Aquacultural Engineering_26_251-262_2002_Intensification-1_Cherax.pdf

InTech-Advances_in_domestication_and_culture_techniques_for_crayfish_procambarus_acanthophorus.pdf

[weedywhaoo]

I am also sure there is a market for red claws in Thailand. I have brought crayfish from Sweden and the Thais love

to eat them. I just hope that the market price is good enough to make a farm profitable. I know that the guy that sells them to Makro gets 350 Baht per kilo and I think the size is about 70 grams each. The way to make a profit is all about getting the feed cost down. I also dont know the FCR for crayfish but would guess that it is close to 2.

I bought a 25 Kg shrimp feed bag for about 1100 Baht but that is still 40 Baht per kilo.

Anyway, next year I will start a fishfarm and hopefully there will be some space left to dig a couple of ponds to play around with. I think a 1000 sqm pond could take about 5000 crayfishes. As crayfish dont need much deep water it would be cool , if it was possible to construct 2 storeys in the pond that would be about 1,5 meter deep.Then you could have 10 000 in each pond. I havent figured out how the feeding would have to be done though.

[crayfish]

Weedywhaoo Great contribution to the thread, superb documents well worth reading, thanks for that.

If you wish to know where I live please send me a pm. I don't want to give out any personal info on the www

[crayfish]

Just a few pics of the new raceway tank.

pic 1 I have put a 45 degree corner where the floor meets the wall. I felt the 90 degree angle was creating a drag on the water. I haven't put the 45 Degree angle on the outside of the "U" section as I want to create a drag there, the water going roung the bend has further to travel on the outside than on the inside, creating a drag on the inside will speed up the water on the outside,( In theory)

pic 2 At the deep end I have placed two outlet valves for emptying the tank.

pic 3 The column filter. The water entering the column is just above half way up ( above the vortex). I have connected an attachment to the end of the pipe that comes with the pump Pic 4. this allows me to adjust the angle of the water.

Pic 5 The basket for the filter pads, not yet finished.

pic 6 I put a plumbing pipe down the middle of the tank to support a mesh cover, still working on that.

Pic 7 The floor of the tank is deeper at the drain end than the curved end. Pic 8

I designed this for drainage purposes without giving a thought to how it would affect the flow, as it turns out it is perfect. I got it running yesterday and there was a good flow of water. When the water enters the tank from the column it is pushing the water around the shallow end ( the curved end), the water then runs downhill to the deep end with assistance from the pump drawing it. It is travelling fast by the time it passes the pump. I had to stop the pump as the column had some serious leaks, I cemented the leaks up yeaterday and will try again today.

Pic 8 The tank is three and a half meters by 2 meters.

I have hardly seen any of the crays in the past 4 days. They are all tucked up in their caves fighting the cold. They are eating well but very inactive. I know how they feel.

[wolfrunes]

The tank looks great. Will you be trying to recreate the hidey spots for the crayfish or keeping the tank plain?

[teletiger]

That is a great tank there Crayfish. My thinking on the filter tank is that with a smaller diameter, more of a vortex can be created. Also placing rounded river stones in the raceway will produce more whirlpools and eddies.

Regards

[canuckamuck]

Looks like you are having fun. Don't worry so much about the leaks in the concrete rings, they will self heal after a few weeks. I am not sure of how it works, but minerals build up and the leaks stop. Most of it will stop in about 4 days. Sometimes it starts again. I have one set of rings that has been up for almost 5 years, it still leaks occasionally for a few days.

I think you are probably ready to go, the only problem I see is the drainage hole could have been larger, that last couple of inches of water takes forever to get out with a small pipe. I retro fitted my tanks with 2 inch drains in the floor and in the last one I put a 3 inch. all of my tank are sloped as well, but only slightly.

Looking good though.

[crayfish]

Yesterday I put the 10 craylings from the small raceway tank (1.2 meters x 1 meter ) into the big raceway tank ( 3.5 meters x 2 meters) When I finished building the tank I let it dry out completely, then filled it with water for 24 hours. The P.H. was 7.2, I then drained the water out and let it dry out again. Refilled it and checked the P.H. after 24 hours ( 7.1 ). I decided to take a gamble and put the craylings in. They have been in overnight and were looking well this morning. The P.H. level was the same this morning. The 10 craylings came to me the size of my thumb nail, they were about a month old. They have lived in the small raceway tank for the last 4 months, 2 months as a normal tank and then 2 months as a raceway tank. They are in very healthy condition.

At the shallow end of the tank it measures 11 centimeters deep and 17 c.m. deep at the deep end. Having a tank with little water in has it's advantages and disadvantages. The advantage is that you don't need to put a lot of oxygen in to the water, and it is easier to create a flow system. The disadvantage is that the crays are open to predators such as owls and other birds of prey, rats and maybe some snakes. To guard against this I have put a cover over the tank, the cover also keeps leaves and other unwanted debri out, including childrens hands The cover is in 4 sections which are easy to remove. Today I am going to experiment with putting more oxygen in, I will put an air tube down inside the overflow pipe from the column filter, in theory this will add oxygen to the water before it enters the tank, will let you know if it works or not. There doesn't seem to be a lot of oxygen created from the overflow pipe. I thought about using a bigger pump, the one I am using pumps 2000 liters an hour, which will recycle all the water in the tank in an hour, but if I use a bigger pump it will increase the speed of the flow which I don't want.

I picked up some broken plant pots from a local builder merchant, for free, which I have placed around the tank.

Assuming the 10 craylings are still alive when I return home, I will put the two big males and the female without eggs into the new tank from the big glass aquarium tank. That will leave two females ( in berry) in the big glass tank, and one female ( in berry) in the small glass tank. The small raceway tank I will use when the eggs hatch. It has been 6 weeks since the first eggs were layed so it can't be much longer.

I emptied the small raceway tank yesterday and put the contents on my pineapple plants, I have done this a couple of times and the plants have benefitted greatly, I am very interested in setting up an aquaponic system above the big tank. Maybe next month. Any ideas would be appreciated.

teletiger suggested that a smaller diameter filter column would create a better vortex, this it would do but it would also decrease the surface area that the sunlight is working on.

[weedywhaoo]

Crayfish,

The system you have looks very nice. It would be nice to visit some day and have a look. If you have any leftover PVC pipes, you can cut them in 4-5 inches long pieces and use them as hideaways for the crayfish.

You can also put in some hey or dried grass in the tanks, the crayfish loves to eat the plankton that comes out when it decays. Since your water depth is not much, please be aware to check temperature in March and April, the water can get real hot if its not in an shaded area.

I have attached some pictures of my tanks with crayfish. I just have a simple system but it is fun to play around with it and test different solutions.

[crayfish]

Happy new year to everyone.

Still no eggs hatching. The eggs on the 3 females look in good condition so am still hopeful for hatching. Maybe they are waiting for the weather to warm up first. I have put the two males and the female with no eggs in the big raceway tank. I have also put 100 tilapia fish in the tank, they are about 1 inch long and seem to live peacefully with the crays, there is no confrontation between them. I put them in to speed up the bio filter system. Today I will buy another 100 and put them in the small raceway tank which at the moment is empty. When I put the 10 juviniles in the big raceway tank 7 of them moulted within 24 hours, they must have thought "WOW" now we can grow. They are looking healthy and have grown from the size if my thumb nail to 3 inches, these are my second breeding stock.

Enclosed is pics of the tank

A new experiment I am trying out. I put straw in a bucket of water about a week ago and let it ferment. The water from this I have added to dry plankton and added an aeriater. just interested to see what effect it will have on the plankton.

I owe a big thank you to canuckamuck for coming up with the raceway design and allowing me to use it ( royalty check forth coming ) I am sure I would be having problems without the design.

Weedywhaoo>>> You also seem to be enjoying your crayfish project, good luck. From your pics I can't see how your filter system works. Would appreciate some info on that.

[crayfish]

Attachments for previous post

Making plankton

[weedywhaoo]

My filter is just a normal aquarium filter bought in an aquarium shop. It contains of some filter pads, some bags of active carbon and zeolite, also some balls with large surface area. I dont know how well it works as a biofilter but the water is clean. I wish I could measure nitrate levels etc but dont have any equipment to do that.

Crayfish, i like your raceway set up, it really looks nice. I am also waiting for my female to give birth. She is now about 3-4 weeks pregnant, so hopefully within a week or two there will be some new members to the family.

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[crayfish]

Weedywhaoo>>> The filter system you are using is the same as the one I have in the glass aquarium tanks, as you say the water is clean, but it is worth investing about 500 baht on litmus strips to keep a check on P.H. levels. I check the water every couple of days and it stays around 7, which is the neutral marker. Litmus strips come with a colour chart indicator, there are about 1000 strips in the box,easy to use. Regarding nitrate, nitrite and amonia levels in the water, this requires meters to measure levels, I have never checked these levels but I do regular partial water changes once a week, about 30% change. This does't guarantee low levels but the water change will keep levels low. Good luck with the new borns

[crayfish]

At last some baby crays!!! The eggs on the female in the small aquarium tank have hatched, about 200 in all, difficult to count. I went to check on them all at one o'clock Sunday morning and noticed she was not holding eggs, but when I looked around the tank I could only see ten hatchlings. I thought maybe she had eaten the others. After a sleep I checked again and found they had all got into the filter system.A pic of one newborn about 8 hours old, about half a centimeter long. This pic shows the size compared to a lighterThese aquarium tanks are great for fish and big crays but not so good for hatchlings. The filter works on an overflow system, water overflows at the top into the filter chamber, the pump sucks the water from the bottom through filter medium and blows it back into the tank. The hatchlings had overflowed with the water into the filter chamber. It took me 2 hours to rescue them without any loss. I have now put a wire mesh on the overflow to stop them entering again.The female I have put in the big raceway tank, I don't think this will create any problems for the hatchlings as her only roll is to protect them from predators and there are none.They seem settled without her.

Still waiting for the other two females' eggs to hatch, the weather has warmed up so maybe soon.

The experiment I tried with the plankton didn't work, the plankton didn't come to life, worth a try

Pics of exoskeleton from the smaller of the big males, it amazes me that they shred their legs, claws and antennas.

The tilapia fish I bought last week have doubled in size, I have never known anything grow so fast. They are well suited to live with the crays, no confrontation and they eat the same food as the crays. Not sure about putting very small crays with them though.

[canuckamuck]

Really glad you are having success with your crays. I am not having the same experience. I think I am down to 7 from the original 16. Not sure what the problem is. They have a very optimal tank. plenty of moving water, plenty of filtration. but still they are kicking off one at a time. The surviving ones seem very strong until they don't. It is possible that it is just too cold up here for crays. But that being said the mornings have been warmer in the last two weeks, and that is when I have had most of the deaths. I have never had one molt.

I assume it is one of three things.

1, They aren't eating. I see no evidence of them eating. The food always just sits there, and eventually gets fuzzy. I have tried many things. what I try the most of is a home made baby food that we make any way. Basically pureed veggies and some meats, eggs and fruit. You know baby food.

i have also tried pig food, shrimp food, crayfish food from aquarium shop, and bananas. I never see them eat.

2. there is something about my setup that is incompatible with them. Currently I am getting some blanket weed which does impede their movement a bit, but it really isn't very much of it. Maybe the fiberglass coating is toxic. this would be weird because before the crays I had fish in there for about 6 months with no problems.

3. It's too cold.

[weedywhaoo]

Congratulation Crayfish,

Its good to see that you made 200 babies. Soon you will have a small farm going. I am still waiting for mine to hatch, and hope that I will be able to see the hatchlings. Sunce my female is in a tank, its easy for the hatchlings to hide. I still find hatchlings from the last batch a month ago in the tank. They are now about 30 mm in size. As soon as I catch them, I put them in another tank but I still catch one or two every day. They like to hide in a red brick I put in the tank. Every morning I lift out the brick and catch a juvenile. I hope that I will be able to get them all out before the next batch is coming.

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[weedywhaoo]

Canuckamuck,

Are you sure that they are dying and not escaping fron the tank?

I have had many that escape from my tanks. When the water gets cold, they eat less and less but that is normal. I wish I could give some advice but dont know what the problem could be, do they have enough oxygen?

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[canuckamuck]

It is pretty easy to tell when they are dead as opposed to missing. They lay on their backs for instance.

As far as oxygen goes, I have actually played around a bit with circulation, trying to limit the water from moving too much at night so that it would throw off less heat. But I have stopped that experiment. Because both time I tried it a crayfish died. No way to know if there was a connection though.

They are getting quite a healthy dose of aerated water. Enough to keep hundreds 20 kg of fish alive previously, and I doubt the biomass in there is even 500 grams at the moment.

[ozzydom]

Sometimes the old saying of "Kill them with Kindness" applies.

I applaud the thought and effort put in by crayfish, canuckamuck and others in building the redclaw environments,but at the same time feel that you are getting to far away from the redclaws natural environment.

Redclaw prefer slow moving turbid (dirty)rivers and static ponds and billabongs, with silt , mud or fine gravel bottoms. This is a far cry from the smooth clean ponds and races shown in your photographs..

I realise everybody is on a learning curve and aquarium style habitats helps in the learning process, but when you advance to growing on your redclaws it will probably be in greenwater ponds with very limited visability ,and this is where you will reap the rewards of your efforts.

I would be tempted to try adding a floor of coarse sand in the bottom of your habitats to make it more natural.

Losses are a part of most learning processes ,so dont get discouraged, persistance will pay off.

[Jotham79]

I am also sure there is a market for red claws in Thailand. I have brought crayfish from Sweden and the Thais love

to eat them. I just hope that the market price is good enough to make a farm profitable. I know that the guy that sells them to Makro gets 350 Baht per kilo and I think the size is about 70 grams each. The way to make a profit is all about getting the feed cost down. I also dont know the FCR for crayfish but would guess that it is close to 2.

I bought a 25 Kg shrimp feed bag for about 1100 Baht but that is still 40 Baht per kilo.

Anyway, next year I will start a fishfarm and hopefully there will be some space left to dig a couple of ponds to play around with. I think a 1000 sqm pond could take about 5000 crayfishes. As crayfish dont need much deep water it would be cool , if it was possible to construct 2 storeys in the pond that would be about 1,5 meter deep.Then you could have 10 000 in each pond. I havent figured out how the feeding would have to be done though.

I think tank culture can be done safely, but when you put them in ponds you risk letting them loose into the environment. There are a dozen invasive species in the states reeking havoc right now and I am sure no one intended it to happen. I'm sure everyone's intentions are good, but the road to Petchabun is filled with good intentions. Please consider this risk when planning you ventures.

[weedywhaoo]

Ozzydom is dead on (as always). I have read many of his posts in the farmers forum and he always comes with intelligent answers. I started with crayfish at my workplace, a condominium with some fishponds in the garden. We put 16 crayfish in a pond and put 4 in an small clean aquarium. After one month the aquarium crayfishes had barely grown at all. In the fishpond where the water was greenish and had pots of lotusflowers and a muddy bottom layer, the crayfishes was double size. The bad part was that many had escaped. Thats why I took the rest home and bought some large blue plastic tanks to raise them in. In these tanks I put dried grass, some plants, called sarai in thai. Everyday leaves fall down into the tanks and they rottents and the crayfish feeds from the animals involved in the rottening process. My first batch of hatchlings has only been eating this stuff, never a pellet or anything else. As they grow bigger I think of giving them vegetables, bananas, potatoes etc and pellets too.

I also think that the water does not have to be chrystal clear as long it has oxygen, the rottening process will eat some oxygen but usually oxygen is never a problem with crayfish.

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[weedywhaoo]

Canuckamuck, I know my question came out sounding stuping, but my english is not so good, and the brain also has its limts. Anyway, what is the temperature of your water?

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[canuckamuck]

the lowest water temp I have seen is 11, but I am sure lately it has not been below 15. I will check this morning and see where we are at. In hot season it does not get above 24. I don't know about the highs in cold season, never looked.

I am at 700 meters elevation and in the far north.

[crayfish]

canuckamuck>>> Really sorry to hear you are having problems with your crays. From what you have said about the problem I would like to make a few suggestions. It would appear that you have an enourmous amount of different kinds of food in your tank. In a raceway tank food doesn't really rot as it would in a stagnant tank with no water flow. In the raceway tank it goes furry, this is creating ammonia which turns nitrates into nitrites which are deadly for crays and aquatic life. Have you been keeping a check on the P.H. levels of the water?? If not I would recommend you buy some litmus strips and check the P.H. level. If it is too high or too low it can easily be corrected, the P.H. wants to be around 7.In the meantime I suggest you take the crays out of the tank, remove all the food and change the water. I noticed from one of your previous posts that you have a pond by your house. Why not put them in there until you sort out the raceway problem. The water from your pond is perfect for the raceway tank, it will be full of plankton and zooplankton.

I have to agree with Ozzydom that we are getting too far away from the crays natural environment, certainly by keeping them in aquarium tanks as I am doing. The raceway tank I still feel is suitable for the crays, I often switch the pump off and allow the water to stagnate for half a day or so, this helps build up the algee which in turn produces plankton. Plankton is vitally important for aquatic life ,not just crays.Yesterday I put a bottle full of live plankton from a stagnant pond into the small aquarium tank to feed the hatchlings, they were all still alive this morning.

Canuckamuck, I may be wrong in what I am suggesting but I don't see there is a lot more you can do, My main suggestion is to get the crays out of the tank as soon as possible, you have lost 9 already and are sure to loose the remaining ones if you leave them in the tank. If you can't put them in your pond then do as Weedywhaoo does and keep them in tubs for the time being.

I feel sure your problem is with the P.H. level of the water. Crays can live in a wide range of P.H. levels, from 6.2 to 8.2. However, if there is a sudden change, say from 6.5 to 7.8 then the crays will not be able to adapt fast enough and will die. It really is important to keep a check on the P.H. levels regularly. The Thai word for litmus paper is Gra-dart litmus (กระดาษลิตมัส). You can get this from a good chemist or stationery supplier.

You also mentioned the problem may be the water temperature, but your crays are dying at temperatures around 15 degrees. This is a safe temperature for them so I don't think that is the problem.There is another possibility, when it was very cold ( 10 degrees ) the crays didn't eat but went into a semi hibernation, at the same time the food you were putting in the tank built up and created a problem with the water. Again I may be wrong.

Good luck with whatever you try, don't give up.We are all still learning.

I am going along with Ozzydoms suggestions and get the setup to a more natural environment for the crays.

Ozzydom>>> One thing that concerns me with keeping the crays in a stagnant pond is what happens to the meat on the crays?? Is it contaminated with high levels of bacteria that make it unsafe to eat!!!! Just a thought.

[crayfish]

Canuckamuck>>> Just a follow up on my last post. I mentioned that the water in your pond is perfect for the raceway tank, it is only perfect if the P.H. level is around 7. Please check it first. The P.H. level of the water I took from a pond yesterday was 6.1, but when added to a tank of water it had little effect on the overall P.H. in the tank. If I put the crays from 7.2 ( which the raceway tank and the aquarium tanks are at the moment) directly into a pond with 6.1 they would die very fast. Please be careful.

[canuckamuck]

Thanks for your help, but I should point out that I do not have an enormous amount of food in the tank. I have some food which is left for several days in hopes that they are eating it. and I have cleaned it out and changed the water about every 10 days or so. Also my tank has a permanent supply of fresh water entering the tank and exiting through the overflow. Probably the water volume is exchanged at least once daily on its own. The water is gravity fed from a stream on our property which originates as a spring a couple of kms away. The water is ideal crayfish water and it has it's own population of freshwater crab in it. I have not checked the PH, but I will get a kit tomorrow.

I would also like to say that I disagree with Dom that the greenwater mud bottom environment would be more ideal. it is true this what people in the industry use simply because of the economics of large scale fisheries. But the crayfish in the wild live in a rocky bottomed clear water with a constant current. That people have success in ponds says that both options are doable but it doesn't not say it is best for the crays.

My setup has continuous current, continuous fresh water, and is only missing natural vegetation and a gravely base to make it a stream. for these reasons and the fact that others are raising crayfish in less optimal tanks, I do not believe the setup is at fault. I am convinced at this point it was either the food was wrong, or I was hit with a disease. At the same time I lost the crays, I also lost about ten tab tim in the other tanks, which is unusual because I rarely have any deaths with medium sized fish.

Today the crays seem quite active, perhaps I am past the problem. The water was 15 this morning.

[weedywhaoo]

As I understand the red claws, they don't enjoy cold water. 11 degrees sounds a little bit to cold for

them to live in. Hopefully now the temperature will rise and there will be no more deaths.

Hope it works out okey for you.

[BEVUP]

Ok didnt read all

but reminds me of my younger days when you would visit someones farm in the country ( talking Yabbies ) & there are other names, all there is is a pond for the cattle or sheep to feed so igues they are eating the odd dead one stuck in the mud & they are territorial