breeding crayfish

[namdocmai]

Yes that's what i have seen, they did it in the morningsun and then were hiding somewhere like they always do.

So i guess i will get baby's soon then, i hope the fish won't eat them.

[soidog2]

I have only a casual interest in crayfish but this is one the best documented topics on this forum.

Great reading.

Congratulations to the OP and contributors!

[crayfish]

Hi everyone and a happy new year.

Will post again after songran. Have made a lot of changes and modifications with the crays and all are doing well.

Crayfish

[kevvy]

They are delicious.

I tried to grow some, but they died on me and had dreams of growing a supply to eat ourselves regularly.

Please post more.

There is another type of freshwater cray from Oz found in the Murray River and has spines...it is without doubt the most delicious one available and grows to a good size, sweet and creamy white flesh...mmm

use to catch them in the murray river around Mildura... great eating ...

kevvy

[mha noi]

Hi Crayfish..

I have loved catching,keeping and eating crayfish whilst growing up New South Wales. I remember years ago searching the net

for hours about them and came across a place breeding them in coke bottles laying horizontal with one end cut off, they were

stacked on top of each other horizontally in a tank. There idea was maximum artificial caves to a tank and giving each cray its own happy place, possibly only useful for fattening stage. Great thread and good to hear there are places to source them in Thai

[crayed]

Crayfish, there is chap here in Malaysia who perfected the Bell siphon, he has also made a belless siphon. His name is Affnan, from Affnan Aquaponics google him and you will learn a lot

[crayfish]

Hi. back again with an update on the crayfish. My last posting was several months ago and at that time I was using a lot of time maintaining the systems I had running. I was running 4 tanks, two raceway tanks and two glass aquarium tanks. The aquarium tanks have now served their purpose, that being to observe the behaviour and eating habits and the development of the newborns. I would rather refer to them as observation tanks. They require a lot of maintenance and are basically a bad design. I don't like having the pump,filter system and fish all in one tank. The filter needs cleaning weekly and is not a pleasant task.

I was having problems with the big raceway tank as it had no roof over it and the direct sunlight was causing algae blooms which turned the water into what looked like pea soup, the crays can live in that kind of water but it is impossible to monitor their condition and how much food they are eating and not eating.

Also with the hot season the water was getting very hot. As you can see from the pic I have put a roof over the tank and covered the walls with cloth and vinyl to stop the cement getting hot which in turn heats up the water. I have also increased the height of the inner raceway walls to allow more water in the tank. I am now running the system with two pumps. One ( on the left side) is pumping water around the tank, the top two inches is moving well while the water at the bottom is moving very slowly, this is important not to have it too fast as it will take the new borns and they will get sucked into the pumps. The one on the right is the filter pump. The vortex filter works really well but not as good as a radial flow filter. I will post after about filter systems, I have 3 different filters at the moment. The water in the tank is crystal clear and has a P>H> of exactly 7.

All the crays are now in this one tank, at the moment about 350 which includes about 150 newborns about a week old. Here is a pic of one of the ten free ones I got when I first started, she is holding about 200 eggs which will hatch out any time soon. I rarely see any during the day, they become very active at around 6 p.m. when they are hungry. A guy from the next village came to see the crays about 2 months ago and wanted to buy the 6 big crays, two males and 4 females, I told him I wanted 5000 baht for each one, he thought that was expensive, I considered it a fair price as 3 of the females were with eggs and all in healthy condition. In the end he bought 200 newborns at 30 baht each which covered the investment I made for the big aquarium tank. Don't know how they are doing but I heard he put them in a wire cage and suspended it in the village reserviour, it would have to be a well designed cage as crays are great escape artists, will go and see soon.

I feel like I have just finished a 6 month apprentiship on breeding crayfish as everything is now running well with a minimum of maintenance, I no longer get up during the night to check if they are o.k. as now I know they are o.k. To this day I have never seen a dead one but I may do soon as my wife licks her lips every time she looks at them. The big 6 breeders are now a fair size but they are only half way to full size, it does not make a lot of sense to eat them now, and they will produce a lot more eggs in the next 8 months. One thing that amazes me about the crays is that they recognise me when I walk up to the tank, they just carry on with what they were doing, but if a stranger approaches the tank they hide away fast.

I am now getting a lot of people in the village showing an interested in the crays. At first they didn't understand what I was doing, for them to wait more than a year to return an investment was out of the question. Now they see them growing and reproducing fast they are keen to learn how to do it.

Have to go now. will post tomorrow showing different filter systems.

[canuckamuck]

Good to see you back here I am interested to hear about your thoughts on filters.

As for green water, I think I had success against it as I was running a lot of fresh water in constantly so it was always diluting down the green.

[crayfish]

Hi. I'd like to talk about different filter systems and get ideas from readers. First we need to decide what we want to do with the filter. Do we want to use the filter to purify the water, or to remove solids, or both. I have used a swirl filter to remove solids incorporated together with a bio system. One was a flat bottom filter and the next one I made was a vortex, both did the same job but the vortex was better as it collected solids better. Pics of these are in earlier postings.

I am still using the vortex with the crayfish tank.

I have set up an aquaponic system which I am using a radial flow filter. ( for some reason I can't attach pics with this posting ) but you can go to youtube and type in "Radial flow filter" to see how it works. It is an excellent filter for removing solids. But the filter that really purifies the water are the plants. Anyone that keeps fish really should do it together with a grow bed. The fish feed the plants and the plants purify the water, and you get all the solids which are used as fertilizer( the best I have ever used). Another big advantage with aquaponics is that you never have to change the water. I am running this system with 100 tilapia fish and have a grow bed with 50 plants, may extend it to 100 plants. I will take some pics this weekend and post on Monday.

Any ideas or suggestions most welcome.

[crayfish]

http://www.youtube.com/watch?v=mKWXkf9j5Qc

Here's the site for the radial flow filter

[crayfish]

Hi. Keeping on the subject of filters. Pic 1 shows the radial flow filter with the lid off. The bell is bolted on to the lid.

Pic 2 shows the water entering from the fish tank. pic 3 and 4 shows the plumbing set up from the fish tank and from the filter to the grow bed.

Pic 5 shows the sump tank.

[crayfish]

At the moment I am running the aquaponic system with Tilapia fish but this can be done with crayfish as well.

Basically the system incorporates 4 tanks. The holding tank( holding the fish). The filter tank(to remove solids) The grow bed ( to remove diluted solids and urine ( assuming fish urinate) and finally the sump tank ( at the lowest point in the system and holding the pump)

Having a sump tank in the system has the great advantage of not having the pump in the same tank as the fish. Having the pump in the same tank as the fish is something I will avoid in any future systems I put together. I am having problems with the pump in the crayfish tank. I feed the crays with plants, straw and grass as well as food I make for them. Every morning I have to clean both the pumps as they get blocked with straw etc.When the non return valve gets blocked it doesn't work and the water will syphon back from the filter system to the crayfish tank. Also every month or two I have to clean out the plumbing connected to the pump as it gets lined with solids that have been running through the pipe work. Having the pump in the sump tank does away with these problems. With the pump positioned at the lowest point in the system everything runs on gravity. Water is pumped from the sump to the top of the holding tank, this overflows to the filter tank which overflows to the grow bed which overflows to the sump tank and the cycle starts again. If the pump stops working the whole system stops with no flooding.

Pic 1 shows inside the holding tank with the outlet pipe going to the filter.

Pic2 shows the outlet pipe which goes to the bottom of the holding tank. Note that I have drilled holes at the bottom end to draw the solids up. I am about to modify this with a 90 degree fitting and a pipe running across the bottom of the holding tank. At the moment it is only collecting solids from one area of the tank.

The water overflows to the filter tank. When it enters it hits the inside of the bell and the solids drop down to the bottom. Some modifications can be made to this such as a vortex bottom and also fitting fins on the inside of the bell to create a swirl motion, the filter would then be classed as a " radial swirl vortex filter. Pic 3 shows the solids gathered in 2 days. The water overfolwing from the filter tank goes to the grow bed where the plants purify the water by absorbing the nutrients etc. This overflows to the sump tank in which I have put some filter medium ( similar to scrubby pads ) to collect any nutrients not absorbed by the plants. I have not had to clean it yet as the water entering the sump is crystal clear. The pump is not in contact with any solid matter so requires no maintenence. I have to run the systems as maintenance free as possible as I am very busy at work for the next few months.

I tried taking a video of the crayfish at 3 o'clock this morning but it came out very unclear. Need to read the manual for the camera and try again.

With the last hatching I now have 5 generations of crays. pic 4 shows one of the last ones to hatch out about 3 weeks ago, they grow very fast during the first month and moult every week until they acquire a hard shell. Sometimes when they moult they loose a limb or two. Pic 5 shows one that has lost both it's claws and some of it's legs. It has been like this for 2 weeks but is surviving.

I have just been called into a meeting so have to go

[crayfish]

Hi, Meeting finished, here's pic 5

Pic 6 One of the big males

After 6 months of keeping crays I am now in the position of having a breeding stock of 5 generations. I am not going to be able to grow them out un the raceway tank, I need an earthen pond to grow them out to full size. At the moment I am working out the investment required to set up the pond, which will include 1. water pump. 2. a roof cover, this is to stop evaporation and stop the rain from overflowing the pond.3. A wall around the pond to keep out predators ( including people) and to keep the crays inside. 4. lighting. 5 An aireator to put oxygen in the water including a motor to run it.6 A sump pump to empty the pond once a year.

The pond I already have but is about 7 meters deep so it needs landfilling so it is 3 meters deep, then a thick layer of clay covering the entire pond to stop water seeping down, then a layer of soil on top of that.

Pic 7 The pond I have. I want to use the soil on the right of the pond as landfill and then I can double the size of the pond. I can keep about 15,000 crays in there.

At the moment I need to work out the investment and then decide to go ahead or not.

[canuckamuck]

Really good stuff, you are quite thorough in keeping us updated.

I will likely be copying some aspects of your system when I get down to making my 5m circular tanks. I do have two tanks already that have a pump at the low point of the filter system and they do stay clean and operational as you mentioned. I also have a partial radial flow filter working in those two tanks, and although it is an accident of design, a lot of waste is separated at that point.

I will also be connecting the garden to my fish filter system shortly. It will not be a return system though, just a drip setup.

I am out of the crayfish business for now, I have fish in all the tanks. I will return to crays, maybe next year after the cold season/

Anyhow, keep up with the info

[David48]

Hi, does anyone know about farming or keeping crays in brackish water 14 ppt

While not a crayfish, a close cousin maybe for this crustacean?

Iced and ready for the wholesaler

After both ponds were emptied, the blue barrels were almost filled.

Brackish water at a Farm just outside Bangkok.

[David48]

A question for Mr Crayfish.

I am curious.

Are you saying that your Crayfish are actually breeding,

producing eggs and those eggs are viable and hatching?

Great accomplishment if they are ...

[crayfish]

Hi David 48

A while ago you asked if anyone has info regarding keeping crayfish in brackish water. I personally have not tried it but if you go into "Ask.com" and type in " can crayfish live in brackish water" you will get answers to your question. It appears that they can tolerate low levels of saline but will not live very long.

There are different species of crayfish some of which can live in salt water, worth checking out.

You also ask me if I am actually having success at what I am doing, the answer to that is yes, I started out, 6 months ago, with 6 crays. I now have 5 generations with a total of about 300 crays and two crays are carrying eggs. I have also sold 200 fingerlings.

The prawns you are breeding look to be closely related to crayfish, but I have no experience with them. Don't forget that breeding redclaw crays is a 2 year project to get them to full size. I would imagine prawns have a faster turnover. The market for prawns and crays is not the same, prawns can be purchaced anywhere in Thailand, but fully grown crays are not so easily found.

I wish you the best of luck with your venture

Hi Canuckamuck

Good to hear from you again. Sounds like all is well with you and your fish. Good luck with everything. Let us know how you progress with your 5 meter tanks, curious to see the filter system you select.

[crayed]

We call them Udang Galah and its very expensive to buy in Malaysia. Wish I could have some to eat right now!

[ozzydom]

A question for Mr Crayfish.

I am curious.

Are you saying that your Crayfish are actually breeding,

producing eggs and those eggs are viable and hatching?

Great accomplishment if they are ...

Because they are AUSTRALIAN and you know what good breeders Aussies are

[crayfish]

Hi Again Still trying.

[crayfish]

Some pics at last. pic1 Male chasing away a female that tried to enter it's tube.

Pic 2 A female, one of the ten freebies I got with the six breeders. Two of these are with eggs.

Pic 3 A fingerling, about 5 weeks old, there are over a hundred in the tank.

[crayfish]

Last attempt at pic of my pond.

[crayed]

Wanted to share with you, just got my Crayfish 6 females and 4 males. I am partly dreading that all the females will berry and am wondering what have I got myself into.

[David48]

Last attempt at pic of my pond.

crayfish ... I sent you a Private Message (PM).

did you receive it?

It shows as a small red box at the top right of your screen when logged onto Thai Visa.

[crayfish]

Hi crayed. You seem to have started out with an imbalance with having 6 females and 4 males. One male will service 4 to 6 females. You will have a problem with the males fighting each other for the females. Would like to see your tank and filter system. What size are the crays? Are they ready to reproduce? They will reproduce at about 4 months old. Make sure they have lots of places where they can hide away, each cray likes to have alternative places to hide, not just one. I can't really give you a lot of advice without knowing the system you are using and the size of your tank. Good luck with the venture.

[David48]

Last attempt at pic of my pond.

done ...

I hope we got that correct?

[crayed]

Hi Crayfish,

At the moment they are in a 4 feet by 3 feet tank with less than a foot of water. I have 2 air stones, a pump and an aquaponic grow bed. Soon I will be moving them to a bigger place in my garden. At the moment they are on my balcony shaded from light. Yes, I too was wondering how come he gave me 4 males to 6 females. I am very worried if all 6 berry at the same time. I have a plan to construct a long box, 10 feet by 3 feet, and in lay it with pond liner. Work on that project should start next week. Do you know how big a water pump I should use? I intend following the aquaponic system to grow vegetables as well. With such a size, how many Crayfish can it hold comfortably? After the females berry can I eat them? I doubt if I can expand some more to have more boxes. Thanks, Annie malaysia

[crayfish]

Hi crayed. ( like the name) Don't worry too much about all 6 females berrying at the same time, that is unlikely. I have had 2 berry at the same time but we have very little control over the situation if we keep them all together in one tank. I would advise you to remove 2 of the males and create a better balance with the females.

Regarding the pump. The tank you are going to build, 10 ft x 3 ft, assuming it holds 1 foot of water will hold just less than 1000 liters of water. I would recommend using a 2000 liter per hour pump to ensure a good flow of water. On the inlet part of the pump you should attach something to prevent the newborns from being sucked up. I have fitted a non return valve which has a cover as shown in previous post.

You ask if you can eat the females after they berry. I removed a female from her offspring once but the offspring were left alone in a tank with no predators so there was no problem. The female's only role after hatching is to safe guard the newborns from predators. If the newborn are left in a tank with other crays there is no guarantee they will be safe. I would recommend leaving them with the mother for a month at least. The new borns will moult every week until they produce a hard shell, this takes about a month. At that stage they will leave the safety of their mother and live on their own. If you want to eat a cray I suggest you eat two of your males. If you do please let me know what they taste like, have yet to try one.

I'm not sure how many crays you can keep in your new tank. You will find it will be overcrowded fast as the females start reproducing. On the first repro they will lay around 100 eggs each, so you will have 600 newborns in the tank when they all reproduce. Are you keeping them as pets or for your aquaponic system???

I am assuming the crays you have are redclaws. The info I give you only applies to redclaw crays. There are many species of crayfish. Redclaws are non aggresive and can tollerate slight overcrowding. I am not sure about other species.

When you build your new pond make sure it has a cover to guard it against the rain and sun.

Keep in touch and let me know of your progress.

Good luck

Regards

Crayfish

[crayed]

Hi Crayfish,

Thank you for taking the time to explain to me. 1st the bad news, 4 Crayfish died. IT's a sad day for me. Counted the berries too early it seems. I son't know they died, if it was the water, all would have died, right?So you ust have been right, the ratio was wrong 6-4 meant "dinner". The chap who sold me the Crays got it from Australia. He's a very kind and helpful person. Anyone in malaysia rading this can contact him if they want to raise Red Claw Crayfish. I will check to see how many females and males I have. It's difficult becase they hide in their PVC tubes and wave their claws menacingly at me. I have a low threshold of pain, lol. I chose the name "Crayed" because after reading how interesting is is to raie them, I was crayed hook line and sinker. They are very nice to eat, firm flesh and sweet. The chap sold me 5, I know, it was too ittle, but then again I thought 5 was just nice. Should have known better. Dipped them in garlic butter yummy. I need to build a canopy for the 10x3 tank first, then get the wiring done, have already ordered the pond liners for the tank. It will be a wooden box in laid with the waterproof canvas. You know the type that lorries use to cover their goods. It is the rainy season here now but soon when the hot season arrives, that 1 foot of water will heat up real fast. Yes, I'll get the 2K pump with some air stones to boot. Once again thanks for all the help. One fine day I'll go see your set up, my daughter lives in BKK. I hope by the time I get there your wife would have had her fill of Crays, so I can buy some from you.

[crayed]

I am having a hard time with my siphon. The grow bed is full of plants for me to dislodge the siphon to see what's wrong with it. The water keeps draining non stop. Yes, I have seen Affnan's version, but not looking forward to moving the pebbles to take a look at the siphon. How come there is so much slimy sludge around the pump, I wonder?