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close this bookBetter Farming Series 30 - Better Freshwater Fish Farming: the Fish (FAO, 1981, 48 p.)
close this folderThe fish
View the documentGrowing your own baby fish
View the documentFeeding the fish In your nursery pond
View the documentMoving your baby fish
View the documentCarrying your baby fish
View the documentPutting baby fish Into your big pond
View the documentFeeding your big fish

Growing your own baby fish

47. A new nursery pond of about 7 by 7 metres, or about 50 square metres, will be large enough to grow the baby fish you will need.


New nursery pond

48. A nursery pond can be built just like a big pond but since the nursery pond is smaller the banks need not be as high or as wide.

49. You can build your nursery pond with an inlet, outlet and overflow like these you used in your big pond.
50. You can also use a shallow trench to let water into your nursery pond (see Booklet No. 29, Items 84 and 85), and use a siphon to drain the water out (see Booklet No. 29, Items 114 to 123), but you will still need an overflow to control the water level in the nursery pond.

51. You will also need a crib to held the fertilizer in your new nursery pond.

52. If you build your new nursery pond next to your big pond so that they share a bank, you will only need to build three new banks for it.

53. If you grow baby fish near your pond, you will not have to carry them far and they will not be hurt when you are carrying them.


Grow baby fish near the pond

54. Fill your nursery pond with water and fertilize it with compost, animal manure or plant material as you did with your big pond. Wait for the water to turn green.

55. Now you are ready to put fully grown male and female fish into your nursery pond. A fully grown Tilapia nilotica is about 20 centimetres long.

56. Be careful to put the right number of male fish and female fish into your nursery pond. The drawing shows you how to see the difference between male fish and female fish.


Difference between male and female fish

57. If you are using your old smaller pond of 10 by 10 metres as a nursery pond and you are using Tilapia nilotica, you will need to put 20 fully grown male fish and 80 fully grown female fish into the pond.


Use Tilapia nilotica in the old smaller pond

58. If you have built a new nursery pond of 7 by 7 metres and you are using Tilapia nilotica, you will need to put 10 fully grown male fish and 40 fully grown female fish into the pond.


Use Tilapia nilotica in a new nursery pond

Feeding the fish In your nursery pond

59. The fully grown fish in your nursery pond will get much of their food from small plants and animals which grow in the green water.

60. When the baby fish are born they will be very, very small and at first they will get all of their food from small plants and animals which grow in the green water.

61. These plants and animals are so small that they can hardly be seen or they cannot be seen at all. But if the water is green in your nursery pond, you can be sure that they are there.

62. So in your nursery pond you must always be very careful that the water stays green so that your baby fish will have enough to eat.

63. To keep the water green, do not forget to put a bucket of fertilizer In the crib In your nursery pond each week. It you are using plant compost or pant material, keep the crib filled to the water line.

64. To keep the full- grown fish in your nursery pond healthy, you must also feed them other kinds of food.


Other kinds of food

65. When the baby fish begin to grow, they, too, will eat the other kinds of food.

66. You can give the fish in your nursery pond many things to eat. But you must be sure that this food is ground or cut very small so that the baby fish can swallow it.

67. You can give the fish in your nursery pond termites or finely ground or cut

· grain mill sweepings
· rice bran
· beer wastes
· cottonseed or groundnut cake.


Food for fish

68. The bigger your baby fish grow, the more food they will need. Feed the fish in your nursery pond

· 500 grams of food every day during the first month
· 1 000 grams of food every day during the second month
· 1 500 grams of food every day during the next months.

69. If you see that the fish do not eat all of their food, give them a little less the next day.

70. If you see that the fish eat all of their food very quickly, give them a little more the next day.

Moving your baby fish

71. After about three months, there will be many baby fish of different sizes in your pond. Then you can begin to take baby fish out of your nursery pond to put into your big pond.

72. Use baby fish which are 5 centimetres or longer to put into your big pond. If there are many baby fish which are 5 centimetres or longer, choose the biggest ones to put into your big pond.

73. The easiest way to take out your baby fish is to use a seine net. If you use a seine net with a mesh size of about 1 centimetre the smaller fish will swim through and you will catch the fish of 5 centimetres or longer. But be sure to put me fully grown fish back In your nursery pond.


Seine net with mesh size of about 1 cm

74. From now on, you can take baby fish out of your nursery pond each month for your own use or to sell.

75. Be careful that your nursery pond does not become too full of fish. If there are too many fish, they will not grow well and your baby fish will not be strong and healthy.

76. To keep your nursery pond from becoming too full of fish, drain all of the water out of the pond each year and collect all of the fish.


Drain the water out each year

77. You can eat the big fish that were in the nursery pond. Item 144 in this booklet will tell you what to do with the baby fish.

78. Wait until the bottom of the nursery pond is dry, then clean and repair the bottom and the banks. Items 145 to 148 in this booklet will tell you how.

79. Now fill the nursery pond with water and fertilize it as you did before. When the water is green, put in the right number of fully grown female fish and male fish. Items 56 to 58 in this booklet will tell you how many fully grown fish to use.


Fill the nursery pond with water and fertilize it

80. In about three months, you will be able to take more baby fish out of your nursery pond.

Carrying your baby fish

81. You must be very careful when you carry your baby fish from one place to another. Baby fish can be hurt easily.

82. When you take the baby fish out of your nursery pond using a seine net, do not carry them in the seine net. Carry them in a container such as

· a clay pot with a cover
· a bucket with a lid
· a plastic bag.


Container

83. When you carry baby fish, you must be careful to

· use only clean water
· keep the fish out of the sun or cover the container with a wet cloth to keep it cool.


Keep the fish out of water

84. If you carry your baby fish in plastic bags, carry the bags in a box so that they will not break. Cover the box and the plastic bags with a wet cloth to keep them cool.


Keep the box cool

85. If you see that the baby fish are gasping for air, put some air into the water from time to time by

· splashing the water gently with your hand
· forcing air into the water with a bicycle tire pump.


Forcing air into the water

Putting baby fish Into your big pond

86. When your new big pond is full of water, you have fertilized it and the water has become green enough, you are ready to put in the baby fish.

87. You already know that if you use Tilapia nilotica in a pond 15 by 15 metres, you will need 450 baby fish which are 5 centimetres or longer.

88. Put the baby fish gently into your big pond as you did with your first small pond. Items 70 to 76, in Booklet No. 27, will tell you how.


Put the baby fish into the big pond

Feeding your big fish

89. You already have learned that the big fish in your pond will get much of their food from small plants and animals which grow in the green water.

90. To keep the water green, do not forget to put a bucket of fertilizer In the crib In your pond each week. It you are using plant compost or plant material, keep the crib tilled to the water line.

91. To make your big fish grow more quickly, you must also feed them other kinds of food. You can feed them

· termites
· tender leaves and waste of banana and cassava
· grain mill sweepings
· rice bran
· beer wastes
· cottonseed or groundnut cake
· slaughterhouse wastes
· animal wastes
· kitchen wastes
· spoiled fruit and vegetables
· left- over food
· chopped grass.


Food for fish

92. With your old small pond, you fed your fish only once a day. But your fish will eat better and grow faster if you feed them two or three times during the day.

93. Prepare all the food for one day's feeding at the same time and give the fish part of the food at two or three different times during the day.

94. Always try 10 feed your fish at the same times every day.


Feed the fish at the same time

95. The bigger your fish grow, the more food they will need. If your pond has 450 fish in it, feed them

· 500 to 900 grams of food every day during the first month
· 900 to 1 200 grams of food every day during the second month
· 1 200 to 1 600 grams of food every day during the third month
· 1 600 to 2 000 grams of food every day during the fourth month
· 2 000 to 2 700 grams of food every day during the fifth month
· 2 700 to 3 500 grams of food every day during the sixth month and until the time that you harvest your fish.

96. It is not easy to know exactly how much food to feed your fish. You must watch them when they eat to learn how much food they need.

97. Feed your fish in the shallow part of the pond so that you can see them eat.

98. If you see that the fish do not eat all of their food, give them a little less the next day.

99. If you see that the fish eat all of their food quickly, give them a little more the next day.

100. If you feed your fish at the same place every day, you will see whether the fish are eating well. If you give them too much, the food which is not eaten will stay on the bottom.

101. Too much uneaten food on the bottom of the pond will take the air out of the water.

102. To make it easier to see if your fish are eating well, mark several places in your pond to feed them.

103. Mark each place by making a square or a ring of light wood or bamboo. Drive a pole into the pond bottom and attach the square or ring, as shown in the drawing.


Attach the square

104. When you feed the fish, put the food inside the square or ring. You may be able to see any uneaten food on the bottom under the square or ring. If you cannot see the bottom, feel with your hands to find any uneaten food that may be there.


Uneaten food