Practical tips for leech farming, easy for beginners to master

      Farming leeches is not difficult, but achieving good returns is not easy. Leeches originally live in the natural environment. In captive farming, if the micro-environment and micro-climate are not coordinated, growth will inevitably be hindered. Tank farming and small-pond water-body farming can hardly produce good returns. Leeches have their own inherent habits. At present, domestication work has just begun, and their wild habits cannot yet be changed. Leeches are very sensitive to chemical fertilizers, pesticides, salt, alkali, acid, water temperature, dissolved oxygen and sudden weather changes. Any discomfort will cause them to escape; when they cannot escape, they can only barely survive.
      A newly built brick-and-cement pond cannot have seed leeches put in immediately. For a newly built cement pond, the alkaline substances in the pond body (Portland cement, calcium hydroxide, etc.) need to be diluted over a long period (about 20 days) before seed leeches can be put in.
      For a newly built farming pond, seed leeches cannot be fully stocked all at once. Only after the overall environmental conditions of the farming pond tend toward a comprehensive balance of the food chain can the stocking amount be gradually increased. One cannot mechanically assume how many kilograms or how many individuals can be put in per square meter; the stocking amount should be determined according to the balance between the specific conditions of the farming pond and the growth status of the leeches. For seed selection, leech seeds that are injured, malformed, hybrid or diseased should all be culled. For leeches with internal or external injuries, if they cannot be identified for the time being, they can be kept temporarily for 2—3 days and then identified. To get a good harvest within one year of stocking, it is necessary to select robust leeches aged over two years as seed leeches. The larger and more robust the seed leeches, the higher the egg production, hatching rate and survival rate; those over five years old are even better, but such old leeches are rarely seen.
      Blood clots are not the only sensitive bait for leeches. When leeches are in a hungry state, anything edible will be swallowed. Untreated blood clots may pollute the water quality, and the cost is also relatively high, so this should be fully considered when using them.
      Leeches have a very broad diet. Benthic mollusks such as snails, mussels, shellfish and their larvae, organisms such as fish worms and water fleas, aquatic mycelial algae and nutrient-rich humus are all their food. Leeches and various aquatic organisms depend on and coexist with one another. As long as the preliminary work is done well and fermented animal manure is regularly added, together with sunlight, air and water, a virtuous cycle of the food chain can be achieved and a sufficient food supply ensured. In this way, costs are low, results are good, and the ecological environment can be optimized; it is more proactive and convenient than feeding on schedule and changing water. If the food chain is matched reasonably, the water quality will be fresh, dissolved oxygen will be sufficient, and plankton and benthic animals will also grow quickly, so the stocking density of leeches can be increased. According to our experience, with 50-80 kg of seed leeches put in per mu of water surface, the food chain can fully maintain a virtuous cycle. As a supplement to the main food chain, some artificial feed can be fed; livestock, poultry and fish feed can all be selected. The feeding amount can be determined according to cost, season and the dynamic quantitative relationship between the physicochemical properties of the farming pond and the farming density. For example, during the peak feeding period for leeches at a water temperature of 22-27 °C, if the water quality is fresh, more feed can be given, before the leeches come out at night to seek food; otherwise, feed a little less appropriately.
      Placing stones, branches and the like in the farming pond is not a good method, and they must not be placed randomly, so as to avoid side effects. The physical materials in the farming pond should be arranged in an orderly manner, and the principle should be to facilitate various operations and save labor, time, effort and achieve high efficiency.