China Aquatic Products Channel original report, how to distinguish between bacterial gills and viral gills? What is the significance of fisheye depression? What does gill mold look like under the microscope? How to distinguish the rotten gills caused by gills, spore worms and melon worms? Here's the answer!
This article is excerpted from the 47th issue of the China Aquatic Products Channel Open Course. The class is divided into four parts: first to understand several common bacterial diseases in freshwater fish, then to understand the main causes of fish diseases, and finally to prevent and control methods. We have excerpted the differences between the symptoms of bacterial gills (based on judgment) and viral gills, parasite-induced gills, fungal gills, gills caused by drug poisoning, and gills caused by deteriorating water quality.
(1) The body color is black, especially the head, which is called "aconitum plague" by fishermen in Jiangsu and Zhejiang. Swimming slowly alone at the edge of the pool or floating on the surface of the water, slow response, difficulty breathing, loss of appetite; in severe cases, swimming alone on the water, not eating, losing response to external stimuli.
(2) The gill filament ends are rotten and blood-filled, sometimes adhered to by lumps of dirt and dirt, and in severe cases, the gill filaments are eroded into columns.
(3) The gill bone is exposed and white, and the inner and outer layers of the gill cap are corroded at the same time, which is hollow from a distance, and the south is called "open skylight".
The symptoms described in the first article cannot be used as a basis for judging the disease, many fish diseases have these symptoms, and we can initially judge from articles 2 and 3 that it is bacterial gill disease.
The first picture in the upper left corner: grass carp has rotten gills, there is a lot of sludge on the gill edge, we also missed a symptom, grass carp's eyes have appeared dented, in clinical practice I found that when the fish appears eye depression, but the eyeball is not congested, you can preliminarily judge that its gills have lesions;
The second picture: the gill filament of the first picture is cut off and placed under the microscope for observation, the gill filament end is rotten, and the cartilage is exposed;
In addition to bacterial gill rot, there are also rotten gills caused by the following 5 conditions, pay attention to the difference with them.
Common ones are gill bleeding in crucian carp and acute gills in carp. How to judge? In addition to judging from symptoms, it can also be judged from the incidence of water temperature and the number of deaths:
Viral gills: the most appropriate water temperature is 23-28 ° C, when the water temperature exceeds 30 ° C, the disease is no longer onset;
Bacterial gill rot: the most suitable water temperature is 28-35 ° C, and it will occur above 30 ° C.
<b>Viral gills:</b> there will be explosive deaths, generally the number of deaths on the 1st day is dozens, the number of deaths on the 2nd day can reach hundreds, the third day and the fourth day can reach thousands, or even more, and from the beginning of death, generally to the third day and the fourth day there will be a peak of death, and the number of deaths will slowly drop after the peak;
<b>Bacterial gills:</b> There will be persistent deaths, such as dozens of deaths on the 1st day, more than 100 on the 2nd day, 300 or 400 on the 3rd day, and 300 or 400 in the next few days.
We often ask everyone what is your water temperature? How many days your fish have died, how many days have died every day, in fact, we are used as a basis for judgment, analyzing whether it may be a viral gill.
Common parasites are gill cryptera, wheelworm, ringworm, three-generation insect, sporangia, small melon worm, ciliate, Chinese flea and so on. In addition to the Chinese fleas that can be directly judged by the naked eye, the others need to be judged by a microscope.
(1) Gill crypter whipworm because the individual is very small, and the reported photos are very small, so many times everyone does not know, it is easy to be ignored, at present in grass carp, carp, koi have been found, and it is more harmful to koi;
(3) Pay attention to the difference between sporangia and small melon worms, there is a spore worm individual is very small, the appearance looks like a small white dot, and the melon worm is very similar, we need to use the microscope to judge.
Spore-induced gills, because the spores are very small, many times everyone does not know, put under the microscope sometimes look black, do not know what it is, but also ignore. From the appearance, you need to use a magnifying glass or use your mobile phone to take a photo, and look closely at the many small white dots on it.
Microscopic observation: 160 times the microscope is required for observation, and it still looks very unclear, and if further diagnosis is required, a microscope under 400 times is required.
This mainly refers to gill mold, many people think that there are fungi in winter, and do not pay attention to fungicide in summer.
(1) The occurrence of gill mold disease is closely related to water quality, and it is easy to erupt acutely when the organic matter content in the water is high, especially in ponds with thick sediment, which are very easy to erupt.
(2) Gill mold mainly erupts in the high temperature season, and May to July is the high incidence season. It is the opposite of water mold.
(3) Symptoms of gill mold performance: sick fish breathing difficulties, no appetite, increased mucus on the gills, bleeding, congestion and bleeding plaque, commonly known as gills, severe when the entire gills are blue-gray, the diagnosis must be examined with a microscope, because the reported photos of gills under the microscope are very few, so many people mistakenly think that the melanin on the gills is gill mold, which is wrong.
(4) It is also worth noting that many times we find that gills are infected by a mixture of bacteria and fungi, so they can be treated by a combination of bacterial drugs and fungal drugs, so the effect of treatment is often more obvious than the single use of bacterial drugs.
(3) Poisoning caused by incorrect use of drugs, such as enemy insects in alkaline water bodies should be used with caution.
Ammonia nitrogen exceeding the standard, salt super high, ph too high these three can cause gills rotten. I remember one year I had a customer, carp gills used a lot of medicine, the effect is not obvious, when I was passing by him, he asked me to help him check it, the water test found that the pH value at 12:00 noon has been 9.4, so I judged at the time, he should be too alkaline to cause rotten gills, so I first let him put the ph down, and then according to the bacterial gills medication, the result was soon the fish disease was controlled.
Through the above introduction we can understand that there are 6 major reasons for rotten gills, so when the fish appears rotten gills can not blindly drug, first of all we have to figure out what it is caused by, that is, what we call the cause treatment, not symptomatic treatment, so many times when we send photos for help, we will not immediately give a plan, will collect a lot of information, will ask you a lot of questions, the purpose is to collect enough information to judge which kind of reasons caused by the rotten gills, and then give you some reasonable suggestions, If you blindly take the drug, there may be no effect of the drug, and in severe cases, the more you take the drug, the more you die.
For information about other common bacterial diseases in freshwater fish and the main causes of fish diseases and their prevention and control methods, please click on the QR code in the large image scan recognition map to understand