breeding crayfish

[weedywhaoo]

Hello Crayfish and others.

I have been living in Thailand for more than 10 years and thought this would be a good opportunity to post something on Thaivisa.

I bought 20 redclaws from Bangkok in July and put them in a fishpond at my workplace. After a month I did a recount and it was down to 11. I guess that they walked out of the pond. Then I bought I plastic container about 1 sqm in size and put them there and also a couple in my fishtank. Well you learn by your misstakes, I now only have four left but believe that it will not go down any further since I put a plastic netting over the tank.

I also visited a crayfish farmer in Sakaeow provins and bought 50 craylings from him. They are growing at a nice pace now. This is just a hobby on the backside of the house but believe it is possible to find a market for these animals.The largest one from the first batch is now weighing 125 grams and his age should be about 7 months old.

Regarding bananas, I give my crayfish bananas and they love to it it. Also the farmer in sakaoew said that feeding bananas makes them taste better. He has forty rai of ponds where he grows crayfish. He sells to Makro and also exports a lot to Laos.

I hope we can keep the thread living as I would love to follow your progress with the crayfishes.

[crayfish]

I got a very pleasant suprise this weekend, some of the eggs hatched out. The newborn crays are some what bigger than I thought they would be. here is a picture of my wife holding one, she is looking very proud and now believes I know what I am doing.

On a more serious note. The crays are doing well, eggs yet to hatch, expect them to hatch by the end of this month.

I am constructing another raceway tank. Have spent the weekend on it. I had to first cut down a large mango tree, about 4 hours work, and also move two concrete tanks to make room for the new raceway. Will keep updated on this

In reply to weedywhaoo, I would be grateful if you can let me know exactly where the crayfish farm in Sakaew province is. I would very much like to visit. A contact number would be great. Good luck with your crays. What are you feeding them on. To reach 125 grams in 7 months is excellent, must be eating high protein.

[canuckamuck]

So I have gotten into the game. 16 redclaws 3-4 inch.

My question today is, how much do they eat? I have only seen one of them eat one time. Normally they just walk over the food.

[crayfish]

http://search.yahoo.com/search;_ylt=AuW2ST2LCrnur6kW40HuQYCevZx4?p=crayfish+anatomony&toggle=1&cop=mss&ei=UTF-8&fr=yfp-t-900

Hi. I wouldn't worry too much if your new crays aren't eating, they need time to settle into their new abode. It might be worth asking from where you purchaced them what they were feeding them. When they are hungry they will eat. I would recommend you put a small amount of different kinds of food in, corn, lettuce, carrot, chicken liver and heart. The above video shows the anatomony of a crayfish. You can see the size of their stomach, which is very small. They only need a very small amount of food. Don't worry if there is too much food in the tank, they will eat it all even if it is old. When the food builds up in the tank, I stop feeding them for a few days or until they have eaten it all. The longest I have not fed them is 4 days. Make sure there are some edible plants in your tank, they will eat them. How many males and females do you have? I noticed you are using metal rods which are supporting your filter system, they seem to be rusting, be careful with rust ( iron oxide ) as too much will kill the crays. Rust breaks down into a very fine powder ( jewellers Rouge ) which is used to polish diamonds and other jewels.

I have been busy with my new tank. Will be finished by the weekend. Finished building the vortex cone yesterday

I mentioned before that crays are escape artists, as you now know. I recommend you put a lip around the top of the walls as I have done on my small raceway tank. For this I used strips that are used for the apex of a roof, these I screwed on. They can also climb up plastic plumbing pipes. I mentioned on an earlier post that I was sat out the front of my house enjoying a beer when I saw three crays walking towards the house. I was shocked as I was sure there was no way for them to escape. When I picked them up I noticed they had just moulted as their shell was soft. There was a 2 c.m. gap between the lid and the top of the wall, I already spotted this but was sure they could not squeeze through with a hard shell, unless of course, they moulted first. Did they force themselves to moult so they could escape!!!! I will say again, they are great escape artists.

The roof tiles you have used are a good idea, but I suggest you also give them pleanty of small private hidyholes, at least two per cray, this will make them feel safe and will settle in quicker.

When a cray escapes from a tank it will make it's way to the nearest water source, stream, river or pond.

Keep in touch

[weedywhaoo]

I just want to mention that new concrete will give off some poisious stuff. Before you put in the crafish, have water in the tank and change the water several times before finally putting in the crayfishes.

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[canuckamuck]

Hey thanks for the tips guys. yes I am aware that the concrete can be slightly toxic, especially at first. However I have very little concrete in that tank that is not sealed with fiberglass resin. The column filter is the only place that raw concrete meets the water. However I am very fortunate that I have a stream with a little dam that sends stream water to my house 24/7 for free. All my tanks get some new water all day long, probably a 100% change at least once a day.

So my concerns about toxins are few. (except when they are spraying pesticides up stream, but there is very little farm land up stream, and we usually know when it is going on.

I counted my crays today. I counted 16, so the ones I thought got away are still around. I have little caves in there for them so they are hard to find in the day time. At night they are more busy.

Crayfish: great job on the cement bowl for your filter. I bet you were glad you didn't have the other rings on before you did that. Mine was a major headache because I had to do it with three rings on. Really tricky. Your tank is coming along, i will be interested to see the final product. Don't fill it too full, it wont have a lot of strength to resist outward pressure. Especially at first. Thanks for the food tips. I will keep trying stuff.

[Mark1971]

Great thread.

To me the widespread commercial farming of crayfish in Thailand seems a matter of when not if.

I have no doubt that the Thai market will accept crayfish as a product. (They eat everything else, after all)

It will be interesting to see the market price which can be obtained & how large the market for the product is.

A few things to consider as this moves from a hobby to a business.

Is there an efficient & reliable way to create a male only Monosex stock?

(Sex selection by hand? Neo female creation by AG gland ablation? Hormone treatment?)

How to achieve the best FCR?

What is the most cost effective feeding & grow out regime?

(Commercial feed? Supplemental vegetable feed? Greenwater system?

Monoculture or polyculture.

eg Crayfish with Tillapia.

[crayfish]

http://www.permies.com/t/13174/organic/Toxicity-Concrete-discuss

Here is a web page regarding the use of cement and it's toxidity. I have kept all my crays in cement tanks at one time or another. At the moment I have 10 juviniles in the small raceway cement tank, they have been there for the past 3 months, I have never encountered a problem with this. Cement itself does not contain any toxic chemicals, it does contain lime, as it is made from limestone. The lime is beneficial to the water as it reduces the acidity and helps keep the p.h. level at around 7. The p.h. level of my cement tank water varies from 6.8 to 7.2 which is well within the safe levels. Crays are in danger when the p.h. drops to 6.2 or rises to 8.2. I use two testing methods for this. One is using litmus paper strips, they are yellow but change colour when dipped in water, there is a colour chart which shows you if the p.h. is above or below 7. I use this method everday but it is only an indicator and not an accurate reading. To get an accurate reading you need a meter which will give the accurate reading on the screen.

The only time cement is toxic is when additives are added, such as hardeners, colour dyes,, inhibitors etc. When I built the cement tanks I allowed them to dry out completely, 5 to 6 days. Then fill them with water, leave for two days and then replace the water, Ready to go.

[crayfish]

http://www.youtube.com/watch?v=AJv58YAE_LM

A vid about p.h. in water. worth watching.

[canuckamuck]

Great thread.

To me the widespread commercial farming of crayfish in Thailand seems a matter of when not if.

I have no doubt that the Thai market will accept crayfish as a product. (They eat everything else, after all)

It will be interesting to see the market price which can be obtained & how large the market for the product is.

A few things to consider as this moves from a hobby to a business.

Is there an efficient & reliable way to create a male only Monosex stock?

(Sex selection by hand? Neo female creation by AG gland ablation? Hormone treatment?)

How to achieve the best FCR?

What is the most cost effective feeding & grow out regime?

(Commercial feed? Supplemental vegetable feed? Greenwater system?

Monoculture or polyculture.

eg Crayfish with Tillapia.

Hopefully we will begin to answer some of those questions as this thread progresses.

[canuckamuck]

_{http://www.permies.com/t/13174/organic/Toxicity-Concrete-discuss}

_{Here is a web page regarding the use of cement and it's toxidity. I have kept all my crays in cement tanks at one time or another. At the moment I have 10 juviniles in the small raceway cement tank, they have been there for the past 3 months, I have never encountered a problem with this. Cement itself does not contain any toxic chemicals, it does contain lime, as it is made from limestone. The lime is beneficial to the water as it reduces the acidity and helps keep the p.h. level at around 7. The p.h. level of my cement tank water varies from 6.8 to 7.2 which is well within the safe levels. Crays are in danger when the p.h. drops to 6.2 or rises to 8.2. I use two testing methods for this. One is using litmus paper strips, they are yellow but change colour when dipped in water, there is a colour chart which shows you if the p.h. is above or below 7. I use this method everday but it is only an indicator and not an accurate reading. To get an accurate reading you need a meter which will give the accurate reading on the screen.}

_{The only time cement is toxic is when additives are added, such as hardeners, colour dyes,, inhibitors etc. When I built the cement tanks I allowed them to dry out completely, 5 to 6 days. Then fill them with water, leave for two days and then replace the water, Ready to go.}

Cement itself is nontoxic, but you and I have built tanks out of Thai cinder blocks. These blocks are toxic. I didn't know how toxic until a friend and I were figuring out a layout for the raceway. We laid out a circuit of new cinder blocks in a non raceway tank, and when we though we liked what we had (nothing cemented just loose blocks) we added some water and a net-full of tab tim fry.

We turned on the pump and watched to see if they would go around the track. But we were called away for about half an hour. When we returned the fish were in big trouble. their slime was hanging off their fins in ribbons and some were already dead. We put them back in their own tank, but all of the fish we used, died in a short period of time.

All of my cinder block tanks are rendered, but my render included a waterproofer and I do not know if this makes the render toxic either. I definitely had a high mortality rate on the first batch of fry. Now the render is old, and I think it is safe. but just to be sure I am going to coat all of my tanks eventually. I did the raceway with fiber glass resin, which works awesome but you have to get done each mix in 10 minutes, and your brush is hard in 30. Fiberglass is also slightly toxic by the way

The next tank I used Shell Super Kote. which is designed as a reservoir waterproofer. Very easy to apply and cheap compared to fiberglass, but as my tanks were used, they were still weeping in areas, so I had mixed results with the application. I need to try again on new cement.

[crayfish]

Canuckamuck

I never gave a thought to the cinder blocks being toxic. I wonder if they use asbestos in the mix, this is not actually toxic but the fibers would lock in the gills and the fish would drown. I may be wrong about this but it is a possibility.

http://worldasbestosreport.org/articles/killing_future/Thailand_experience.php

The roof tiles you have over your tank contain asbestos. You can smell it when it is cut. In the linked article it states that 90% of asbestos used in Thailand is used for cement pipes and roofing material. If asbestos is the reason then coating it with cement would solve the problem.

Just to be safe I would recommend you paint the roof tiles with a vinyl house paint, this will lock the fiber in.

[canuckamuck]

If there is asbestos, there is no worry, it is under a coat of render and the fibers would not be able travel. The real problem is the chemicals used to make the cinder blocks, and keeping them locked in.

[crayfish]

Hi A pic showing the progress of the new raceway tank. Notice the floor level. I have sloped it down to the left so it will allow me to clean out the floor sediment. I will put two outlet pipes at the lower end. Hope to have it finished this weekend.

Still on the subject of breeding crays, I have 200 pineapple plants. They are about 5 months old and have been growing steadily. Last week I cleaned out all the sediment from 4 tanks and using a watering can I poured it over the plants. Within 3 days I saw an incredible difference, They seem to have shot up another 2 inches and have turned a nice rich green colour. This has got me interested in aquaponics and am looking at different designs.aquaponics.bmp This pic is basically what I am looking for but I will have the plants over the raceway tank and the water returning directly back into the tank. Still thinking how to set it up.

Completely off the subject, just like to show you a pic I took last night of a tookgair, its a young one about 5 inches long.

This is a very high definition picture so the pic can be magnified many times to see fine detail.

canuckamuck. Forgot to mention... put a few hands full of straw or hay into your tank. Either put a stone over them or as I do push the straw into a pvc pipe with straw protruding from each end. As the straw disintergrates the crays will eat it. They also like eating grass. Last night my eldest daughter caught a bag of small silver fish, about 2 c.m. long, no idea what they are called, but the crays enjoyed eating them, they were all asleep this morning after the feast.

Regarding food, In less than an hour you can produce enough pellets to feed your crays for the next month. For this you will need a small bag of rabbit pellets ( these can be fed straight to the crays as they do not float), A bag of catfish food ( this floats ) A bag of cat food ( floats) . Take two or three hands full of each and grind it into a powder in a blender. Put the powder to one side. Next: cut half a lettuce and any other vegetables into small pieces, drop them all into boiling water for no more than 5 minutes. Take out and allow to cool down. Grind all the boiled veg in the blender. Next: mix the powdered pellets together with the boiled veg adding water left over from boiling the veg. Make this into a paste. Roll it all out on a tray about 1 c.m. thick. Put it out in the sun for a day then cut it into pellets. You can also mix Ram ( rice husk) with the powered pellets before mixing with the boiled veg. There are many things that can be added to this recipe such as dried fish, chicken etc. I wouldn't recommend feeding the crays with only these pellets, they still need raw food to get fiber.

[crayfish]

I think I have found the problem with cinder blocks ( breeze blocks). They are made from cement and flyash. Flyash is a byproduct of coal which is burnt in power stations to produce electricity. Flyash is a mixture of different chemicals that are left after burning. For more info type in "flyash" and "how to make breeze blocks" on a search engine. Flyash is what makes the blocks light.

[crayfish]

I think I have found the problem with cinder blocks ( breeze blocks). They are made from cement and flyash. Flyash is a byproduct of coal which is burnt in power stations to produce electricity. Flyash is a mixture of different chemicals that are left after burning. For more info type in "flyash" and "how to make breeze blocks" on a search engine. Flyash is what makes the blocks light.

[crayfish]

I think I have found the problem with cinder blocks ( breeze blocks). They are made from cement and flyash. Flyash is a byproduct of coal which is burnt in power stations to produce electricity. Flyash is a mixture of different chemicals that are left after burning. For more info type in "flyash" and "how to make breeze blocks" on a search engine. Flyash is what makes the blocks light.

[crayfish]

I think I have found the problem with cinder blocks ( breeze blocks). They are made from cement and flyash. Flyash is a byproduct of coal which is burnt in power stations to produce electricity. Flyash is a mixture of different chemicals that are left after burning. For more info type in "flyash" and "how to make breeze blocks" on a search engine. Flyash is what makes the blocks light.

[crayfish]

Is there an alternative to breeze blocks???

[canuckamuck]

Yes you could make forms and just pour concrete.

Also there are gypsum blocks, often called Q-con. But they need special glue for mortar and they have their own render too.

More expensive as well.

[canuckamuck]

Thanks for the crayfish food recipe, I think I will give it a go. I am also going to look for commercial shrimp food.

[canuckamuck]

Here's a few pics of my crays

[weedywhaoo]

They look wonderful, have you any idea of the weight?

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[canuckamuck]

I haven't weighed any, I have only had them a week. But It would be a good idea to find out what they weigh now so I could track their growth.

[weedywhaoo]

Mine are about 7 months old and the weight is 80-125 grams.

[weedywhaoo]

I just found out that one female is carrying eggs. They have orange colour, does anyone know how long time it takes before the craylings will fall off the mother, and is it necessary to separate the mother from the craylings, so she dont eat them?

[crayfish]

Canuckamuck Your crays look in very healthy condition.From your pic I notice you are keeping them in very little water, do you have your tank covered to keep out preditors especially birds. Another thing worth considering is the cold weather, if they are not submerged in water the wind may make them very cold. I keep mine in about 35 c.m. of water. How many males and females do you have. I think 4 females to one male is a good ratio. I have 2 males, the bigger one fathered the three females and is still trying to get his legs over the fourth female but she is showing no interest, she is the biggest of the 4 females and the only one not to lay eggs. The first female laid her eggs on 13th. November, 5 weeks ago. The weather has been cold lately which will affect the hatching time, I expect them to hatch by the end of the month. The second female laid eggs on 18th. Nov and the third on 1st. December.

Weedywhaoo. You ask wether it is necessary to seperate the craylings from the mother. The mother will only eat her offspring if she has nothing else to eat. When they hatch they will stay with her for about 4 to 6 weeks, they moult every 7 days, after 3 or 4 moults they produce a hard shell , feel safe and leave the mother. ( This info only applies to Redclaws, other species I don't know.) The craylings and the eggs are in danger if there are other species of aquatic animals in the tank. If you have them in a tank with other redclaws I don't think the others will make a problem, but I am not sure of this, I will know for sure soon and let you know. Just make sure all the crays are well fed. I keep small fish ( Guppies ) in the small raceway tank to eat the mosquitoes, but when the crays have eggs I will take the guppies out or they will eat the eggs. When I first started breeding crays I bought small red crayfish ( not redclaws) I didn't want to breed them. When the first one had eggs I put guppies in and they ate all the eggs. This I didn't like doing but I didn't want hundreds of them, I have enough work on my hands with the Redclaws.

I have nearly finished the new raceway tank, got rained off yesterday. Have made a few modifications to it, will show some pics tomorrow.

I am experimenting with plankton. On Friday I put a table spoon of dried plankton in 2 litres of water, a teaspoon of salt, mixed it together, put an airstone in and waited. Sunday morning I couldn't believe it when I saw millions of plankton swimming about. I can't figure out how a dried powder can come back to life. I will do another batch when this rain has passed but this time I will place the container in direct sunlight and see if there is a difference. I also have a jar of it in my fridge to see how long it will store for. Plankton is essential for the new borns, it is all they will eat for the first few weeks. If you are making your own food for the crays as I detailed earlier, remember to keep all the crumbs that are left over and crumble them into tiny pieces to feed the new borns when they are a few weeks old.

I am happy I started this thread. It is nice to see how many people are interested in the subject and good to have people to talk about it with. Most people around me are tired of listening about redclaws as it is all I ever speak about. On this thread we all seem to be gaining a lot of knowledge on the subject and hopefully it will all materialize into a successful venture. Lets organize a b.b.q. for some time next year. I have never eaten a crayfish but imagine they are delicious.

[wolfrunes]

Following this with great interest and would like to visit your place some day to look at your whole set up

[canuckamuck]

In my pics the water is being changed, so I took the opportunity to take some pics. Normally they are in 40cm of water.

[DerkMR]

Regarding the concrete tanks the usability of fresh built tanks is a lot depending of your water quality.

If your water already is alcalic then the fresh tanks would put it into toxic levels during the first time.

So either you change the water frequently over 2-3 weeks or - a recipe I heard of but never tried - you put in some chops of banana tree trunks.

They start to disintegrate and leave a layer of bacteria over the surface which then will no longer have a strong influence on the water chemistry.

My es FIL built some small tanks using the big wastewater rings and cement for the bottom. The introduced Guppies did well, but they do in nearly every water, in another ring he put some fish for the kitchen and not every fish survived.

Bye,

Derk