Fish lice are one of the more common parasites , with a flattened body , broad dorsal carapace , and a distinctly ovoid shape. There is a pair of large suction cups, 5-30 mm long, good at swimming. Firmly adsorbed on the surface of the host body in the form of a suction cup, a disc-shaped stinging mouthpiece is used to feed blood and mucus.
▲ Fish lice under the microscope
Fish lice can constantly change parasitic fish bodies in the water, and the water temperature begins to spawn when the water temperature reaches above 15 ° C. From birth to maturity to spawn, it takes 50 days at 17 °C water temperature and 20 days at 28 °C. When parasitic in large numbers, koi will remain stationary at the bottom of the pond, or accumulate in the corner of the pond, or float on the surface of the water, without appetite.
Parasitism is usually chosen in areas with sufficient blood circulation, such as the base of the fin and around the mouth. They often leave the fish after they have eaten enough to find another host.
There are many barbs on the ventral surface of the fish lice, like a nail adsorbed on the fish body, constantly crawling on the fish body, and with its ventral barbs, mouth spines, large pieces, stabbing, tearing through the parasitic parts of the fish body, secreting poisonous juice, resulting in extreme uneasiness of the sick fish, swimming and jumping sharply in the water, seriously affecting the appetite, the fish body is emaciated, because the fish lice suck the blood of the fish, causing fish anemia, there are many wounds on the surface of the body, prompting the fish body to infect microorganisms, resulting in fish death.
▲ Fish lice parasitizing the mouth of a fish
Parasitic diseases rely on koi's own resistance is not curable, to timely treatment, the traditional to the enemy insects, copper sulfate, mercury nitrate as a therapeutic agent, such traditional drugs are mostly toxic, and many parasites long-term use of a single drug, will produce drug resistance, often need to increase the amount of medicine to produce effect, but high concentration of drugs will also cause harm to fish. Therefore, it is advocated to rotate the use of some new drugs.
△ Fish lice parasitic on the pectoral fin
Prevention and control measures:
1. If adult worms are seen, 1% concentration of potassium permanganate solution can be directly applied to the growing site, the parasite can temporarily lose its activity, use forceps to remove the disease and insect, and pay attention to preventing the occurrence of bacterial diseases.
2. Put 90% crystal enemy insects 0.25-0.3 grams per cubic water body, sprinkle the whole pool, or put 90% crystal enemy insects 0.5-1.0 grams in 10kg of water, bathe and wash the sick fish for 10-15 minutes, and take the drug for 3-4 consecutive times.
3, with 0.5% C-body 666 powder 0.01 g dissolved in 10kg of water bath washed sick fish for 10-15 minutes.
4, with potassium permanganate 0.5 g dissolved in 50kg of water, bathe the sick fish for 30-60 minutes, put back into the pool (tank) where the water has been replaced.
If aquarists find that there is this thing on their own fish, do not be too nervous, although the fish lice may add some trouble to the carp owners, and it may not be good to kill the fish, but generally as long as it is handled, there is basically not much of a thing, after all, it is visible to the naked eye, much better than the invisible bacteria.