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Best method for fry tank

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  • Best method for fry tank

    HI all , what is the best method used in rearing the fry? I want to know how to keep filteration in the fry pond without the fry being sucked into the pump. I plan on using a flatable swimming pool for my spawn and want to know what I need to do about filteration. I plan on removeing the parents and letting the fry hatch in the pool. Do I need to use extra air stones in this pool? With 1000 gallons of water how much do you think I would need to change everyday or can I use a good filteration and not have to do water changes every day.

    Also I would like for someone to post a pic for me on the forum. I need to email this pic to you so you can post for me as I am unable to do this without someones help.
  • #2

    In the tank I used last year. I only needed a bubbler in the middle of the tank for the first few weeks. After the fry were big enough, I switched to a 300gph mag drive pump with an aluminum window screen intake. I did not see any fish getting stuck in this.
    Attached Files


    • #3

      Forget the fry tank, get them in the mud pond.
      I spawn straight into my Mud ponds. Hold the parents to spawn in a 3mtr x 2 mtr x 1 mtr floating net. As soon as the fry hatch, I drop the net down in the water, so they can leave when they fancy.
      If the fry pond is good enough to raise the fry, it's good enough to spawn the parents.


      • #4

        To prevent fry from being sucked into the intakes make a prefilter out of reticulated open cell foam. One needs to correlate the gallons per hour and the surface area of the foam to avoid having the fry trapped against the foam itself. Please note that one can utilize reticulated open cell foam as a biological filter. Used in this manner, a foam augmented system contributed to a 13% increase in body mass at five weeks.

        The inflatable pool seems a convienent idea but is problematic. Most vinyl liners have an algaecide added to its formulation. This will eventually will leech out but will be toxic to the koi. My guess is that it will kill the fry, given enough exposure.

        If the pool is of insufficient mass, temperature fluctuations will occur depending on ambient temperature and wind conditions. Ever changing temperatures add stress to the fry resulting in stunted growth and a lower immune responses.



        • #5

          I would look for videos on spaning koi from a japanese farm. You might not know why they are doing what they do but there are numerous reasons. one thing you'll observe is that they do not spawn in a tank and just remove the
          parents. They also remove the eggs to a different location. Maurice cuts the handling time down by going direct. but with shiros and showas you want access to cull at 2-3 days.
          Dick Benbow


          • #6

            KFG: You've made it pretty clear that you are determined! I think Maurice and Dick are giving you great advice. But, sometimes, I guess, a person has to learn their own way. And learning by doing can teach a lot, even if it is a tough way to go. This first time, consider just raising up 50 fry to 2" size to get the hang of it. Keep it small scale so you can control things. Then I expect a lot of things may become clearer. Best of luck.


            • #7

              You should forget the swimming pool idea straight away, get yourself a purpose built show vat if you must use something like that. As stated above, the material is impregnated with chemicals that will kill your fry as they leech out. I've also heard of these pools reacting with the chemicals that is often used by koi keepers, such as malachite and equivalents etc.

              Also, regarding water changes, you should only fill to 18 inches when you spawn and immediately after spawning change 50% of the water. YOu need to repeat this each day for a few days and then reduce the amount. Only bring the water level up as the fry get bigger, too deep and you'll harm them with the water pressure.


              • #8

                Thanks Guys for the advice, If I do the spawn in the mud ponds how long should I wait before removing the parents or do I just leave the parent in the pond? Would I lose alot of eggs this way?


                • #9

                  Hi Mike avoiding the hard way is the way to go. Majority rules. I dont want to make a lot of mistakes and still have a great deal to learn. I had rather take the advice of someone that has already done this with success. I think you are right about Maurice and Dick, mother nature has always been the best way in most cases for me. Years back when I spawned and raise tropicals I found out to raise fry in water from a branch and was able to raise fry verse trying to raise them in clean well water, there was not enough live for or mycro food for the fry and lost most all fry because of this. Studys after study did me no good. When I went in God direction well I was on my way to success.


                  • #10

                    Hi Judy,
                    you can take quite different approachs for rearing your fry. Every one has their pros and cons. Is up to you to decide which one you prefer for your first attempt.
                    If you want to rear a limited number of fry, and learn as much as possible, then maybe you should consider using a rearing tank.
                    Contrary to a mud pond, you must take good care of the fry on a daily basis, but you will be able to keep a close eye to them and check their development easily. I did that last year having filtration on right from the begining (turnover rate=total volume/1'5 hours), as well as UV clarifier and aeration. Don't botter about live food: start your own cultures of protozoa and rotifers first, then Daphnia/Moina, and when these go exhausted swicht to Artemia if necessary. You just have to add stuff from your cultures to the rearing tank. In 15 or 20 days your fry will be able to feed powdered (grounded) pellets.
                    A small swimming pool (foldable, for kids) is allright provided you clean and rinse it carefully in advance. I do that three or for times during two days before using a new pool. Also make sure the base is well protected from puctures.
                    The mud pond can be much better if you are going to raise big numbers of fry, but many things will go unnoticed since the water won't be clear. First of all you have to prepare your mud pond in such a way that, by the time the eggs hatch, it must be:
                    1) full of rotifers and protozoa, and Daphnia population way up
                    3) no predators (either adults or larvae) present
                    Seems that many breeders start several mud ponds in one season with the hope that at least one will be in optimal conditions by the time of egg hatching.
                    Good luck,
                    Attached Files
                    Diego Jordano
                    Cordoba, Spain
                    A.E.K. web site
                    pers. web site


                    • #11

                      I can always try both ways and see what I like the best. I just dont want to lose of whole lot of my fry, I think I should be able to due the mud ponds ok. I am going to start and fertlize my pond when I do my spawn and by the time I move them their should be enough food for the fry. I am thinking ferterlize about two weeks in advance of my spawn. Right Guys. Someone please correct me if I am wrong. Also I have learned that my mud ponds only need to be 3ft. deep instead of 6ft.

                      My mud ponds for my fry will be small and still do I need air in the ponds and if I do what do I need to use?


                      • #12

                        You will always need to remove the parents as they soon begin to eat the eggs. The male can go back with the males or community pond. You need a quiet place or just a female pond for the female. She needs time to recoup and get rid of her scent before going back to any kind of community situation.
                        Dick Benbow


                        • #13

                          Hi Dick how am I going to do this without mashing alot of the eggs. And thanks for answering my question. I know you are to do this if you put in a pond that is clear did not know about a mud pond.


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