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Thread: Appetite

  1. #1
    Fry
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    Jul 2008
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    Appetite

    Hi guys...I have been following this forum for sometime now and learn a lot about koi keeping.

    I have a question : how to increase the appetite for my koi?
    I have read somewhere, the healthy koi should eat all the food within 10-15 min. But mine, it takes about 30 min or more to finish the food.

    Any suggestions?

  2. #2
    Oyagoi Flounder's Avatar
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    Dec 2005
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    Warm high Q water.

    How big are your koi? How big & deep is your pond?

  3. #3
    Fry
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    Jul 2008
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    Hi Flounder,
    I live in S.E. Asia, so the climate here is warm enough..ranging from 28-30 C.

    My pond is about 50 ton and the deep is 1.5-1.8 meter. I have about 30 koi with size ranging from 40 - 75cm. I know, it is over stock.
    My filter : Sand filter, 8 multi chambers up and down filled with brush and Japmat...and also Bakki Shower with bioball.

  4. #4
    Fry
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    Jul 2008
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    Additional info.
    I used to feed them 600 gram/day, twice/day. I have reduced to 400gram/day and still take 30 min to finish. The reason I reduced is most of the time they could not finished the food.

    Btw, my water parameter is ammonia 0, nitrite 0 and nitrate 50.

  5. #5
    Daihonmei
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    Sep 2006
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    Koi are temperate water fish. Meaning they have evolved as wild carp to cope with seasonal changing light and water temperatures, as well as 'feast and famine' in their diet in terms of calorie intake and protein/roughage mix. So the ‘thing’ that stimulates the appetite is first and foremost the biological clock within the fish. This has not changed in the 75,000 years of the modern carp’s existence and certainly not by the fact that it was moved to the mountains of Japan a few thousand years ago and made colorful in the last three hundred years.
    So science shows that these fish are most metabolically efficient between 68 F and 76 F. You will notice for instance that your koi’s appetite spikes in later September when the evening air becomes cool but the days are still sunny. The whites get remarkably glowing and the sumi is deep and rich and the fish? They climb over one another to get a pellet. You are witnessing, at that moment, a ritual and instinctual behavior repeated in millions of schools of this species since the receding of the last ice age.

    Meanwhile in the backyards of the western koi keeper, there are indeed things you can do to ‘stimulate’ appetite (with a small ‘s’). Keep water quality high, as already mentioned and feed food with a ‘bait scent’ on it. A few pellet manufactures spray a lure on their product and declare the food irresistible! J You can do the same yourself with cat fish oil sprayed on homemade food or pellet food. You can also feed sweet tasting starches like sweet potato and increase a fish’s ‘greed’ for taste.
    And withholding food one day a week can trigger more agressive feeding. Especially if rotated within an otherwise fixed rountine.
    In the end, it is not how much food you get in the koi that makes them grow. It is understanding their nature, their biological clock and their need to have a stress free environment with NO negative environmental feedback. JR

  6. #6
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by Icon001 View Post
    I have read somewhere, the healthy koi should eat all the food within 10-15 min. But mine, it takes about 30 min or more to finish the food.

    Any suggestions?
    If everything is otherwise fine, don't worry about it. The concern is that a lot of food will be tossed in the pond and not be consumed. Beginning fishkeepers tend to overfeed a great deal. The food then decomposes, adversely affecting water quality. If all the food is being consumed, what's a few minutes? I feed floating pellets in the evening, tossing a dozen or so pellets at a time. As soon as most are consumed, I toss in some more. It often takes my koi 45 minutes to let me know they have had enough. I then check the skimmers for pellets that did not get consumed and remove any I find. The concern is not that the gals took 45 minutes to eat their fill, but that they did get all they wanted and none was leftover to decompose.

    The idea of feeding only what is eaten within 5 minutes or 15 minutes, or whatever, is one of those rules of thumb created to help new hobbyists avoid common newby errors. It is nothing more than that.

  7. #7
    Daihonmei PapaBear's Avatar
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    Ok, so you have around 13,000 US gallons (50 metric Ton) of what sounds like well filtered water. You have 30 Koi of a size range that works out to about 8 lbs per fish or 240 lbs. In your climate (which isn't very seasonable variable) you should be feeding around 2% of body weight per day for growth, or about 4.8 lb of feed per day (2177 grams).

    That is a LOT of food for growth with that many Koi, even in a 50 Ton pond.

    It is also a lot more than you are feeding. For heavy feeding, even in your warm climate, Koi need to have the food spread out over more feedings per day. Since they don't have a stomach they can only consume as much at one time as their intestine will hold, which explains to me why it takes them so long to eat. They are gut loading up to the point of being "full" and the rest just has to wait for them to pass what has been digested before they can take in any more.

    Smaller amounts spread out over 5-10 feedings per day would allow them to take the food in at a more natural rate (Koi are continual grazers, not bulk feeders) and it might give you better performance. A programmable auto feeder or demand feeder might be a good option for you to consider.

    Another thing to bear in mind is that 28-30 deg C water temperature (82-86 deg F) is on the high side of their "prime growth" metabolism and may effect their appetite and digestive efficiency negatively.

    In any case, changing the amount of feed will change the bioload to your filter, so maintaining high quality water will become more of a challenge.
    Just my thoughts.
    Larry Iles
    Oklahoma

  8. #8
    Fry
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    Jul 2008
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    Many...many thanks for all you replies JR, MikeM and Larry.
    I hv seen few ponds of my friend which use chiller and set the temp. at 24-25 C. And yes, the appetite increase and also the skin quality...and this will be my last alternatives as the electricity bill concern.

    Also, heard about spreading the feeding time....meaning I hv to buy auto feeder due to time concern.

    So, is that mean I under feed my kois as mentioned by Larry with that load and size, I should be feeding them 2kg / day? What actually will happen if I under feed them?

    Btw, the reason Im concern about appetite is I want to have koi with masive body. And i know, this is to do with genetic and bone structure.
    Is that possible?

  9. #9
    Fry
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    Jul 2008
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    Water Quality Measurement

    Other and most important....
    How do you measure high quality water besides Ammonia, Nitrite, Nitrate, pH, GH and KH.

    ORP? TDS?

  10. #10
    Daihonmei
    Join Date
    Sep 2006
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    Besides the usual check to see that your biofilter is operating properly and managing the load ( I.E., Ammonia, NitrIte and NitrAte) you want to do a
    Stress test on your closed system.
    That is, you want to understand the limits of your pond with your number of fish and your feeding technique. This would include how rapidly your NitrAte builds between what is considered normal water changes. If a 20% water change once a week is not keeping up with the rise of your base level pollutants ( like NitrAte) then you are too crowded or feeding too much for the system- and that means negative feedback on the fish and a loose of agressive appetite.
    ORP will tell you how oxidative your water is. But that reading alone ois meaningless without a reference to your pH and water temperature ( oxygen saturation levels).
    TDS is a test of general rising pollutants and can hint of the limit to your systems alkaline reserve.


    In your setting ( warm tropical country) I'd monitor the shift in PH and also most important of all, your oxygen saturation levels for temperature as you have little margin for error. The story of your ORP will make more sense if these things are known.
    You could use the TDS system but in your country the ORP/pH and oxygen saturation level for temperature will be more directly linked to the fish's well being as in warm water, oxygen and pH crash are far more telling.

    JR

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