ansihkgt

Feed rate and ajustments

8 posts in this topic

Hello all,

Are there any feeding chart that i can follow as a reference ? I found one on internet land but just not sure if it would be ok to use it as a reference. I have 700 tilapia and the growth rate looks good so far. they are about 20gm average.Added them two months back.

The link above has formula to estimate the groth rate of tilapia mentioned as FCR 75%. How true is this ?

Quote

Feeding

The growth rate of tilapia is controlled by water quality. temperature and feeding rates. If the water is correct tilapia like to eat more than almost anything else. Feeding four or five times a day is best as the tilapia digestive system runs on a two to three hour schedule. A basis for how much to feed can be calculated from the chart below.

Let's say you have about 100 fish that weigh 35 grams each. Your tank will have 3500 grams of fish to be fed. From the chart you can see that 35 gram fish should be fed about 4% - 7% of their body weight per day. We'll take 5.5% for this example because the 35 gram fish are in the middle of the weight range on the chart. 5.5% of the 3500 grams of fish we have is 192.5 grams of food. We can then split the 192.5 grams of food in fourths to make the four feedings for the day.

If you are checking fish weight on a weekly basis, you can do the calculation each time you check fish growth and up the feed amount each week. If you're not you can calculate the new fish weight by taking the weight of food you have fed in one week times 0.75. In our example this would be 192.5 grams x 7 days = 1347.5. Take 75% of this, 1010.6 grams (the 75% allows for the food conversion rate for tilapia). We’ll round this to 1000 grams. You then add the 1000 grams to the original weight of the fish at the start of last week 3500 + 1000 = 4500. This will be the new total weight of the fish in the tank. Now you should have 100 fish totaling close to 4500 grams, at 45 grams per fish. Look this up in the chart and calculate the new feeding rate for this week. We'll say 4.5% or 4500 grams = 202.5 grams per day.

Appreciate anyone could comment on it.

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Hi ansihkgt,

That info appears fairly accurate.
If I recall correctly, some Tilapia farms in Thailand are achieving better than a 1:1 FCR... in Optimum conditions.

Cheers
Toga

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Thank you Toga.

 

Any idea how the figure 75% was determined ? is it from the FCR. FCR is Feed conversion Ratio which is obtained with the formula Feed Given / weight gained.

I am trying to get max fcr for my investment on the feed and don't wish to over feed them.

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Hi ansihkgt,

Generally speaking, FCR is a historical industry average of harvest results.
This can vary greatly from species to species... with some producers claiming FCR's up to 1:1.4 (140%)

The most important consideration, and one ever so often overlooked / ignored by hobbyists, is that these results / references are from professional operations, with high quality filtration, aeration, water pumps etc... AND a trained eye overseeing it all.

Best advice is to start at the very bottom end of such references to feed rate. CLOSELY observe feeding patterns and regulate accordingly.
Just because an article says xyz size tilapia will eat 100grams of food per day this month (IE:3kgs), does NOT mean your system has the bio capacity to filter that quantity of waste.

Much more information about your system is required to give a comprehensive picture of your circumstances.
Do you have filtration ? What is your water flow for 12,000ltr pond ? What grow beds do you have / or plan to have ? Raft / NFT / iAVs / F&D ?

Start a thread in the systems area and add some pictures.

Cheers
Toga

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Thank you Toga.

The fish tank is made of concrete. The system has a 3000 liter swirl filter, a Bio Filter, a Mineralization Tank, a Sump tank and 4 grow-beds. Here the idea was to grow more of fish than plants hence an undersized grow-bed. HAP 120 aerator aerating the fish tank, Bio filter and mineralization tanks. A 1500 AC pump.

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Hi ansihkgt,

Sounds like you have things well under control with your setup.

How old is the concrete tank.. have you had difficulty with high pH ?

Cheers
Toga

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So far nope. pH has always been stable between 7.0 and 7.6. My target fish size is about 300gm. Forgot to mention that my design is a CHOP system.

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i mean i had the cement tank cured before adding fish into it and its been 2 years now. My flow rate to the swirl filter is 8300 lph

Edited by ansihkgt (see edit history)

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