Catfish Mortality: What to Do When Your Fishes are Dying
Mortality will not just occur; there must be a cause. It will be a good and wise decision to tackle the root cause of the problem and not just address the problem on the surface. You can only be sure of the root cause of the problem through laboratory tests which will help you to know the cause and specific solution to be applied. If the use of drugs will be required, you will know the specific drug to use. This is why a farmer must not wait till the time his fishes will stop eating before taking appropriate action. Once you discover mortality consistently, take action by applying the right therapy.
In Nigeria of today, there are not many drugs specifically manufactured for catfishes. A pharmaceutical company who will research into drugs for catfishes will do well in Nigerian market. All these while, catfish farmers in Nigeria have depended so much on poultry drugs to cure catfish diseases. Little wonder that some of these drugs will not work as expected.
Prevention is better than cure, says an adage. Mortality in catfish can be totally eradicated or controlled to the barest minimum if these two conditions are met:
Good water quality
And healthy feed
Every suggestion as regards prevention of catfish mortality is either related to good water management or feed management. Here are the highlights of what you need to do to limit mortality in your stock throughout a farming season:
Never stock your pond without adequate pond preparation. If your pond is not properly prepared, cycles of pathogens causing disease will not be broken. It will be a wise decision on your part as a catfish farmer to do the necessary as regards pond preparation. For lime treatment of your ponds, 250kg of lime is recommended per acre of pond surface. Also under pond preparation, ensure all macro-organisms (tilapia, frog, etc.) are eradicated from your pond before introducing new set of fishes. Do not allow residual infection to spread to your new stock through poor pond preparation.
Ensure that water quality entering into your ponds is not compromised. As much as possible, prevent turbid water from flood entering into your pond. Also take note of water coming into your pond from adjoining ponds. If you allow water from disease infected ponds to enter into your pond, sooner or later, you will start to experience the same diseases in those ponds where your water source is derived. Never allow water coming out of ponds with bigger fishes to enter into ponds of smaller fishes. It is possible that bigger fishes have developed resistance to certain diseases in their ponds. Smaller fishes receiving water from bigger fishes with disease will be at the risk of infection.
Proper monitoring of feed consumed by your stock of fish is very important. Certain feed and feed ingredients can induce mortality if some toxic substances are found in them. Make sure you buy floating feed with pedigree. Select your feed ingredients well.
Keen observation of fish stock on a daily basis is what every farmer must learn to prevent heavy mortality. Before feeding, farmers must look out for any behavioral change in their fish stock. Prior to mortality is behavioral change. The change in behavior of these fishes may be in the way they react to your movement, sound of your vehicle, change in their swimming pattern, their activeness and so on. It could also be a change in their response to feed. Instead of rushing to consume their feed, they run away as soon as feed touches their water. A proactive farmer should observe these changes in behavioral pattern and act accordingly. Stop feeding as soon as you notice any negative change in the activities of your fishes. Never force your fishes to eat what they cannot eat.
Routine medication can be applied to prevent mortality. This is done by adding certain mild drugs into your feed periodically (e.g. once in a month). However, experience has shown that there are certain challenges related to routine medication in catfish feed. It can lead to development of resistance to certain drugs causing them to be more vulnerable when they are sick and the same drug is applied.
What to Do When Mortality Occurs
Many have asked questions on what exactly to do when mortality occurs. I must say that the cause of mortality will determine the method to use in controlling it. For reference purposes, here are the steps you need to follow in the process of controlling mortality in your farm:
i) Identify the root cause of mortality through intelligent observation and laboratory test. Some experienced farmers can diagnose the cause of mortality through close observation. However, observation might not work sometimes. To be on the safer side, the need for laboratory test is very crucial. Farmers are to take a sample of the following for laboratory test in the case of mortality:
The diseases causing mortality could be water-borne or feed-borne. Only laboratory test will let you know the exact cause of the problem.
ii) Analyze the results of your test or observation to know what exactly to do. Cure for water-borne disease is not the same as the cure for feed-borne disease.
iii) Embark on application of right treatment at the right time, based on the analysis of your results, to prevent uncontrolled mortality.
Cure/Treatment of Catfish Diseases
As said earlier, the treatment of catfish diseases is based on the cause identified. In essence, there are different kinds of treatments based on the cause. Generally, below are the treatments for catfish diseases:
a) Drain out the water from your pond if results reveal high level of pathogen in the pond water. The pond water drained out should be replaced with fresh, unpolluted water. If your fishes are still very young, ensure you introduce the fresh water gradually into your pond to ensure your fishes are not stressed up.
b) Where you don’t have enough water, salt can be used to treat your pond water. Salt treatment is always applied by farmers because salt contain chlorine, and chlorine is a good water sanitizer. Dissolution of industrial salt into your pond water will release chlorine gradually into your water to get your pond treated. However, effectiveness of such treatment is not always guaranteed because farmers may not apply the right quantity of salt into the pond water. To ensure proper treatment of your water with salt, the volume of the water in your pond must be known. Bear in mind that salt can be used to treat your water and also used to kill your fishes if it is applied in wrong quantity.
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c) Iodine treatment can also be applied to treat your pond. The use of formaline (Formaldehyde) is a nonconventional treatment for catfishes because of the health implication on end consumers. If you are to use formaline at all, you must observe a withdrawal period of at least five months before the fishes are sold to the market.
d) Feed-borne mortality is treated by immediate withdrawal of feed causing mortality. Farmer should discontinue using a feed that is causing mortality not minding the cost of purchase.
e) Fishes that have been affected by pathogens are treated by applying the appropriate medication based on the recommendations on the laboratory test results. As a matter of fact, laboratory test will tell you the specific type of drug to use.
f) At times, all you need to do is to stop feeding for a minimum of two days and a maximum of five days if nothing is wrong with your water and feed.