Introducation

Bangladesh is a tropical country. Its climatic factors like temperature, rainfall, air, light, etc are favorable for the production of various crops. It is also a Delta  country. As a result, its topography and soil conditions are favorable for the growth of certain crops . Think about the vast expanse of flat land we have! Also the few hills we have are not very big and high. Bangladesh is crisscrossed by hundreds of rivers- big and small. They give the land a lot of alluvial after each flooding. This alluvial soil is fertile and easy to prepare for cultivation.

A country plough  is a traditional Agriculture implement. Every village carpenter can made it. And you can buy a plowshare from any village blacksmith. The carpenter first makes its body by shaping it out of a log. Then he shapes the upper end of the curved wood into a handle. He then fixes a share to the top of the lower end of the body. Finally, he fixes a wooden beam to the body. Now it is ready for use in the field. A pair of bullocks draw the plough while the farmer holds the handle firmly. He can use the plough to break up and loosen the soil. A country p lough has some advantages.He can easily carry it from one place to another.It is simple to made, easy to operate and is not expensive. But if you want to do some deep plugging and control deep-rooted weeds the country plough is not the right tool.
In these days of fast- increasing inflation and wage restriction, are finding it essential to do everything they can to reduce their cost of living . Growing one’s own fruit and vegetable has become necessary, as well as pleasurable, for many of us. Home freezers are now very popular, and, if used intelligently, do not take long to repay their initial cost. You can grow you produce cheaply from seeds of plants, pick it at its peak, eat what  you want, and freeze the rest so that you can still enjoy it in its prime when it is out of season, and without having the trouble of going to the shops.
But a far larger part of the average family’s food bill goes on protein foods, important which, like fruit and vegetables, is an important part of a healthy, well balanced diet. Cheese and eggs are still relatively cheap sources of protein, have risen phenomenally. Even the cheaper’ cuts of meat and types of fish are now expensive, and a home-produced source of these foods is the best way to make the maximum savings. Traditionally, these sources wore chickens, which produce eggs, of course, as well as meat, and rabbits. But nowadays people are also turning to fresh- water fish such as rainbow trout, carp and trench, which can be raised in ponds and ornamental for the unproductive goldfish, golden ore, golden ruddy, etc.
Although to many people this may sound a novel idea, it is nothing of the sort. All the medieval monasteries had within their walls one or more fishponds stocked with carp. The monks were obliged to eat fish on certain days  for religious reasons,  and sea fish would have been inedible after  a long journey from the coast .a fish pool was also a feature of many of the garden of great house, and before the eighteenth century, served the same purpose. Then the style of large houses and their gardens changed the pool became ornamental and was planted out with water lilies, and goldfish were introduced. In the more rural districts of France many small pools are stocked with carp still, and provide fish for the table.

How Fish live


A fish is a cold-blooded  creature which breathes in oxygen extracted from the water, not form the air as on the case of mammals .there are three classes of fish and they are primarily differentiated by the of skeleton that they have. Most British fresh-water fish (including rainbow trout, and teach have) fall into the third group skeleton, while those of the other classes have cartilage skeletons, with jaws some cases and without in others. Many o f these fresh –water fish with skeletons of bone structure have swim bladders, the function of which is discussed overleaf.
Body shape of fish :
There are great variations in the body shape of fish over the whole range of species. The most usual, however, is a streamlined one like that of he typical fish. Certainly this is approximate shape of rainbow and teaches

How fish move :
As mentioned before, some fish have a swim bladder, which is situated in the middle of their body. It is a silvery, gas –fish bag which, permitting a fish to float and swim at any depth in the water without rising or sinking. Any fish that have not got this organ must keep on the move continuously.

A fish can follow any course it wants through the water by using its fins. Two pelvic and each of dorsal, caudal (or tail) and anal fins. this, however , varies form species to species and some fish lack pelvic or pectoral fins, while others lack a dorsal or caudal fin . in some  instances several fins are amalgamated. An example of this is in the eel, whose very long dorsal and anal fins merge with the caudal fin, giving a continuous edging so fin along the whole body. The fins control stability and direction.

The senses :
Fish have eyes with a very wide range of vision. Between the eyes and the mouth, on the uppermost side of the head, are two small vents –nostrils, but the fish does not breath through these. Instead they are used for smelling only and have nothing to do with the respiratory system.
There is a faint line running on either side or the body of a fish, which is known as the lateral line. This consists of a series of highly sensitive cells, which, by means of records of pressure, indicate distances and warn of hazards. It is, in fact, a built in radar system. In addition, some fish have barbells, which are fleshy filaments hanging from their mouths, which they as feelers.

Breathing

Breathing :
Fish have a special mechanism in the shape of their gills for extracting oxygen from the water. This gills are positioned on either side of the head, a little gill, the gill filament and the gill lamella, are protected by the gill cover. The water enters the girls by way of the mouth valve preventing the water fro, flowing out. It leaves through the skin fold which functions as a valve at the opening at the rear of the fill cover. Any food particles are sieved out by gill rankers on the  inside of the gill lamella, in which there is a oxygen in the water in to the bloodstream of the fish.

Feeding :
Many fish are carnivorous, but they do not all prey on other fish. The most usual food consists of a variety of bottom-living and mid –water organisms, such as insect larvae, mollusks, small plank tonic crustaceans etc. Some fish live on insects which fall on the water surface. Often, when these are plentiful, they do not touch other food. Some species of fresh-water fish live exclusively on vegetation. Carp and teach to like eat water plants.    

The digestive system :
As a fish does not breathe through its nostrils or its month, but by means of its gills its gullet or esophagus leads from the mouth straight into the body cavity. Usually a fish does not chew its food, its teeth being used to grab food or prey. The food is swallowed whole. Consequently the gullet is capable of stretching to a considerable extent. Food passes next into the stomach, which is folded into a U-shape. The first half (9cardiac), which is the larger, is capable of being distended considerably by a good meal.

The second half (pyloric)  leads through a sphincter (circular) muscle, which joins the stomach and the intestine. Just beyond is the pyloric cacao, which has numerous long, narrow sacs in it, rather like the fingers of a rubber glove. There are usually more than thirty in a rainbow trout. These increase the surface or the absorptive area of the gut and sometimes aid digestion by secreting by secreting digestive juices. The length of the intestine varies appreciably from one fish to another.  It exists in the cavity of the body of the fish as a loosely coiled tube. At its far end it opens to the outside by way pf the anus, which is situated just behind the pelvic fin.

At the forward end of the body cavity is the blobbed liver with the gall bladder from which the bile duct liver with the gall baser from which the bile duct leads to the intestine. In this same area there are scattered the pancreatic tissues. The spleen is joined to the back arm of arm of the stomach.   

The digestive juices are secreted into the stomach, the pyloric caeca and the front end to the intestine. Other secretions are injected from the pancreas area. Bile, which emulsifies the oils in the food, is injected from the liver through the bile duct. These all contrive to break down the various foods into compounds that can be assimilated by the body of the fish through cells in the walls of the intestine. The unwanted, undigested remains pass out as faces through as faces through the anus.

Environment


Temperature of the water :
The temperature of the water in which fish live is very important. In the first place it has very considerable influence on its oxygen content, because the solubility of any gas decreases as the temperature rises. Water that is satisfactory for a particular species when it is colder might prove lethal when it because too hot because the oxygen has been driven off.

The optimum temperature of the water varies for different fish, so they will not naturally live together in the same environment. as an example, that for brown trout is between 45 F (12 c) and 60F (15c) whereas that for carp is between 72F (22c) and 77F (25c) . These figures are consistent with the fact that brown trout revel in the cold, well oxygenated  waters of, mountain streams, while carp are happy in warm oxygen is much lass abundant.

Rainbow trout tolerate higher temperatures and lower oxygen concentration than brown trout. Consequently it is possible to come to a compromise and have some ponds in which rainbow trout and carp will live reasonably will together and flourish.

Fresh clean water :
The water in a pool containing fresh-water fish must be fresh. No account must it become brackish (there is a rare possibility of this happening if the pool is replenished form an old well ). It must not be allowed to because stagnant, because it might contain substance. Obnoxious to fish. There must be no decaying organic matter present as these produce toxic gases harmful to fish.

Looking After Fish

Feeding fish :
In well-established garden ponds, fish survive without being fed from the outside if there is plenty of vegetation on which water insects can breed. The one exception is when fish are introduced into a newly made pool, because the vegetation and other natural foods have not built up to the extent needed to sustain fish without some additional contribution. Supplementary feeding should be carried on for at least the first season after stocking such a pond.

The food which various types of fish eat differs to some extent. Several, such as perch, pike and zanier, live largely on other fish, even to the extent of cannibalism of their own species. It is important therefore that such predators are not introduce into a gender pool stocked with, say carp pr rainbow trout , which although they will eat fry, largely liven on insects, larvae etc. and especially with  carp, pond, vegetation. There are some fairly well-defined rules covering the feeding pf fish dept in a garden pool, whether for decorative or edible purposes. To produce healthy fish these rules must be adhered to strictly. In the first place, if fish are to grow quickly for the table, it is essential that they should have ample oxygen. Another factor is the temperature of the water. When it is warm there needs are greater than when it cools down in winter. In fact when it is rally cold their food intake falls almost nothing. Between late November and early March it is seldom necessary to feed fish at all. 

There are, however two times in the years when it is important to be sure that they are well fed. One pf these is at the end  of summer and early autumn –September and – October –when a supplementary high-protein ration should be provided, because natural life in ponds diminishes and it is important for the fish to be fortified to withstand the winter, during which time they rely on nourishment stored in then own bodies. The other time is in the spring when insects and other natural foods are only just beginning to come to life again. At these two periods it is an advantage to supplement their natural diet with chopped-up earthworms, vegetable proteins, yeast products, shredded meat etc. There is an excellent proprietary high-protein food in the form of floating pellets, produced by a leading manufacturer of trout and salmon food. 

It is a complete diet of fish meal, vegetable proteins, yeast and cereals to which is asses a proportion of shrimp meal, vitamins and mineral. As the pellets float, the fish come to the surface to nibble them. The pellets are easily removed if they are not soon devoured, so there is no risk of pollution. During the rest of the year other food that can be given includes baked breadcrumbs, oatmeal soaked in hot water, mashed peas, cooked potatoes and, cheapest of all, household scraps. If fish are being raised for the table and are table and ate to grow satisfactorily in a reasonably short time, they must be given an amole amount of food in addition to that which they get from pond life. The operative word is ‘ample’ as a guide, they should have no more food than they will consume in five minutes. The amount fish will eat in this period depends on a number of factors, such as whether they are din and active, and the temperature pf the water. Normally, one feed a day, if it is pf the right size is sufficient.

There is one danger period –when you go away for two or three weeks’ holiday. a kindly offer form a neighbors to feed the fish should be gently refused, because the fish may well be inadvertently overfed. It is quite safe to leave the fish to fend for themselves.

Feed Meter


Feed meter :
While it is probably better to regulate the fate of feeding fish by experience, there is one device that can give some guidance –a feed meter. This is a temperature gauge which indicates when and when not to feed the fish


Fish feeder :
You can also buy a floating food dispenser, which distributes food automatically when is active by the fish. It is suitable for all types of feeding stuff and for all size of fish. They take just what they want and there is no risk of pollution. This device is excellent for use during holiday times and also during mild periods in winter. In a larger pool it might be necessary to install several of these floating fish feeders.


Removing fish from a pool :
If ever you have to empty a pond containing fish you must remove them to a safe place such as a larger barrel or water butt, of a temporary pond constructed in a corner of the garden by digging a hole of a suitable size and lining it with polythene sheeting. if for any reason the fish have to stay out of the main pool for a long time, a temporary pond is the vest solution . it is important, however to make sure that the temporary pond is large enough, so there is no danger of. Overcrowding :


When removing fish from the pool never catch them in your hand as this might damage their scales and remove the protective mucus covering their bodies. This renders them more liable to disease. Fish must always be caught in a net. There are several designs of nets. Usually the framework and handle are made of aluminum. Satisfactory nets have an opening pf 120sq. ins (770sq.cm). There are also nets available with (2.25m) long handles, which are telescopic. In addition there are hand fish nets which have a wire framework and a rot-proof, very fine mesh. Hand nets vary in size, but the largest opening is about 10*9ins (25*22.5cm). They are particularly useful for removing fry from the main pool to a nursery pond if breeding takes place. If the fry are not taken out, until they reach more than I in. (2.5cm) long they are likely to be devoured by the larger fish.

Predators Pests & Diseases


Submerged oxygenating plants :
He important plants can be quite simple planted in small plastic pots or baskets. If they are bought planted up they usually have a lead weight attached to them so that they usually have a  lead weight attached to them so that they sink to the bottom. If you plant them into your own pots in the garden, a weight such as a heavy  stone should  be tied to each pot. Alter naively  they can be weighted and dropped unpotted on to a half in. (1.25-cm) layer of washed gravel spread over the bottom of the pool,in which they will root. This method prevents becoming too invasive. As they have little root they can be planted at any time.

Deep marginal plant :
These are planted in polythene crates on bricks a few inches below the surface the water and gradually  lowered until they reach their required depth. Popular deep marginal plants are Appleton distances (Water Hawthorn), which requires a depth of about 12ins (31cm) and which must have its crown 6 ins (15cm) below the surface or the water in order to survive frost.

Floating plants :
Excellent representatives of this group are which is damaged by frost and should be winters indoors Hydrochloric Morse-range (Frog-bit) and Stratification alongside (water Soldier Or water cactus). These plants are merely placed on the surface of the water at any time during the growing season.

Water lilies :
These beautiful plants are planted  in crates supported on bricks so as to allow at first 3-6ins (7.5-15cm) of water above them. When they commence to grow they should be gradually lowered until they are at their right depth. When first planted, all the mature leaves and supply roots should be removed with a sharp knife.

Maintenance of aquatic plants :
Water lilies in containers must be re potted  between mid-March and June every three or four years.Marginal plants should be thinned and replanted periodically. In the autumn all excess growth and dead leaves etc. must be cut away from water plants with a sharp knife to prevent pollution. Water plants growing in baskets and pots should be fed with fertilizer from time to time. This may be done by placing  a ball about 1.5ins (3.75cm)  in  diameter, made of equal parts clay and bone meal, into the soil alongside the plant roots. Alternatively you can buy a proprietary  fertilizer in a perforated sachet, which is placed near the roots of the plants.

Pests :
Pests that attack aquatic plants are water-lily black fly water-lily beetle and brown chin marks moth. Fortunately these pests are consumed by the fish. Sometimes, however, it is necessary to hose them off plants so that the fish can get at them. 

Wild aquatic plants :
Do not introduce plants form rivers and streams into a garden pool, since plants from wild sources might bring diseases and parasites.

Bath

Fish have eyes with a very wide range of vision. Between the eyes the mouth, on the uppermost side of the head, are two small vents- nostrils, but the fish does not breathe through these. Instead they are used for smelling only and have nothing to do with the respiratory system. There is a faint line running on either side of the body of a fish, which is known as the lateral line. This consists of a series of highly sensitive cells, which, by means of records of pressure, indicate distance and warm of hazard. It is, fact, a built-in radar system. In addition, some fish gave balers, which are fleshy filaments hanging from their mouth, which they use as feelers.

Breathing :
Fish have a special mechanism in the shape of their gills for extracting oxygen from the water. The gills are positioned on either side of the head, a little behind the eyes. The vital parts of the gill, the gill  filament and the gill lamella,are protected by the gill cover. the water enters the gill by way of the mouth, which contain what amounts to a non-return valve preventing the water from flowing out. It leaves through the skin fold, which functions as a valve at the opening at the rear of the gill cover. Any food particles are sieved out by the gill rakes on the inside of the gill arch. The water then flows through the gill lamells, in which is a fine network of blood capillaries to absorb the oxygen in the water into the bloodstream of the fish.

Other Meances to Pond Life

Frogs :
Frogs are more a nuisance than a danger the fish, except  that on rare occasion fish are injured by colliding with them. If, however, they are allowed to breed they can reach a disturbance with  their croaking. they are prolific bedder an a pool can soon become rewed with tadpoles. these should be removed with a net. Frogs live most of the year near water, but in February congregate in ponds to breed.The best way of dealing with frosh is to cover the pool with a net, particularly during late winter and spring.


Toads :
Similarly, toads in a garden pool are more a nuisance than a menace, by filling it with tadpoles and by devouring food that is needed for the fish. They live mainly on dry land, but always return to the water in which they were born in late Mach and April for breeding. They can be kept out by covering the pond with a net.


Newts :
Newts can be a danger to fish because they include small fish in their diet. They live most the year on dry land but enter the water to breed in early spring and leave it again at the end of the breeding season.Although they are usually rather smaller than mature frogs and toads a net will stop them entering a fish pool.


Great pond snail :

Although most water snails do no harm, the great pond snail or fresh- water whelk should be removed from a pool if it appears because it does considerable damage to water plants. The snails can be recognized because they are longer (up to 2 ins / 6.25) then other water snails and they have a long narrow shell with a very pointed end. If any eggs appear on the water plants they should be hand-picked. The adult snails can be trapped by putting a lettuce or cabbage stump in the pool. This should be removed very frequently and any snails  on it shaken off.

Breathin & Feeding

 Breathin :
 Fish have a special mechanism in the shape of their gills for extracting oxygen from the water. The gills are positioned on either side of the head, a little behind the eyes. The vital parts of the gill, the gill filament and the gill lamella, are protected by the gill filament and the gill lamells, are protected by the gill cover . The water inters the gill by way of the mouth, which contains what what amounts to a non-return valve preventing the water from flowing out. It leaves through the skin fold, which functions as a valve at the opening at the rear of the gill cover Any food particles are sieved out by the gill rakes on the inside of the gill arch. The water then flows through the gill lamells, in which there is a fine network of blood capillaries to absorb the oxygen in the water into the bloodstream of the fish.
Feeding :Many fish are carnivorous, buy the they do not all prey on other fish. The most usual food consists of a variety of bottom-living and mid-water organisms, such as insert larvae, mollusk, small plank tonic crustaceans, etc. Some fish live on insects which fall on the water surface. Often, when these are plentiful, they do not touch other food. Some species of fresh-water fish live exclusively on vegetation. Carp and tench like to eat water plants. 

Pollution Prevention

The first important thing that has to be done to maintain a healthy colony of fish is to see that pollution does not affect the condition of the water, because the toxic substances from it are the commonest cause of fish dying.Water is usually polluted by decaying vegetable matter, such as fallen leaves, branches and twigs.In a garden pool these come form two main sources- dying water plants, especially the large lush leaves of water lilies, and the leaves of deciduous trees and shrubs; and perhaps to a lesser extent these days, soot from the atmosphere. Other sources of danger that must be closely guarded against are dead frogs and fish.
As mentioned precocious two of these sources of trouble cam be averted by anticipation. Always ensure that your pond filter is free from debris and from August onwards look for dying leaves, silks, and seedpods on water lilies; deep marginal water plants and other aquatics are likely to discard them generously. As they appear they should be removed. When the leaves of marginal plants die off, usually in October they should be cut off.
Leaves from neighboring trees are shrubs, the other serious source of pollution in a fishpond, Should be prevent from falling into the water by spreading a net over it in good time.such a net might also prevent the fish being stolen stolen by herons, kingfisher and other predators. Typical nets range in sizer from 12*9ft(3.6*2.7m) to 12ft (10.8*3.6m). They are made of  ¾ -in (1.9) plastic mesh. Spread the net right over the pool. If the surrounds are soft ground, fix it firmly in position by supplied with the net. Otherwise hold it down with bricks pr pieces of stone. Normally it is placed in position after the pool heater( if you are using one) has been installed. 
 If leaves have already fallen into the pool, possible because of an unexpected gale, before the net has been put into position,they can be removed by dredging the bottom with a fish net. This can be done more effectively if the pool is first half- emptied.Sometimes leaves and debris collect on the surface of the water before they sink to the bottom. These can be removed with a had fish net.An improvised device for this purpose consists of a piece of chicken wire fixed over the prongs of a garden fork. The netting should be about 16ins (40cm) wide than the prongs and should have the last 5ins (12.5) on either side besent up at an angle of about 20 degree to the vertical. The great care when using this device in a plastic- lined pool 
Regular partial replenishment of water with fresh supplies also assists in keeping down the concentration of toxic substances. In fact, if the water looks dark green or blackish in October  and you do not want to empty the pool completely, the water can be pumped out to the half-way mark and replaced with fresh.   

Overhauling mechanical equipment :
Late autumn is a good time to check the pumps, clean them and have them overhauled. At the same time, examine fountain jets and clean out any holes that have become stopped up. Also check all the electrical cables and connections. Give this equipment very special attention: because of the proximity of the water in the pool it would be dangerous if there were a breakdown in the insulation. It might be advisable to ask an electrician to check the circuits.Late November to early December is a very suitable the low temperature at this time of year means tat oxygen concentration in the water is relatively high. Also fish at the  rime are rather less lively and their demand for oxygen is less. This makes it easier to shout off the pumping plant for a shout time.Nevertheless the fish must be kept under observation. If any sings of oxygen starvation appear, deal with the situation immediately by playing a jet of water on to the surface from the nozzle  of a garden hose held about 3ft (0.9m) above the water.
Polythene, though not very satisfactory  for lining a permanent  pool, is nevertheless very useful for making a small temporary pool, since this material is cheap and easily rolled up for storage when not in use.  It is particularly useful for making a pool to be used temporarily for housing fish and aquatic plants, such as water lilies, when the main pool is being cleaned out or repaired. In addition whe3n fresh- water fish, such as carp, breed in captivity, the tiny young fish should be removed form the main pool and kept separately form the main pool and kept separately until they are 2-3ins (5-7.5cm) long. If this is not done, some of the larger fish may eat them. Wooden barrels or metal drums are often used for this purpose, but unlike polythene sheeting they need a lot of storage space when not in use, and this is seldom available in today's small gardens. A temporary pool could aslo be used to house any fish that show signs of being unwell.


Safety of children and pets :
Perhaps the best way of dealing with the3 problem of safeguarding children and pets is to  cover the whole surface of the pond very securely with strong, fine nylon mesh which, when tightly secured round the edges of the pond and supported on timer cross members, can withstand the weight of several small children. A thick pl;panting of  marginal plants would deter young children and  animals form stepping on to the netting. The mesh will not spoil the appearance of the pool because aquatic plants will grow through it. It will not affect the fish at all. Another method is to fence the pool in around its entire perimeter to a height of up to 3 ft (90cm) , with either a green plastic- cover wire fence or similar 2-in . (5-cm) mesh chain-link fencing supported on metal or wooden posts . The latter is less prominent. Admittedly both kinds may look unattractive, but you can soften the effect by planting groups of herbaceous perennials at intervals on the outside of the fence. If your pool is a raised one, say 2ft 6ins (75cm)- 3ft (90 cm) above the ground, there is no risk to small children.