Different Types Of Fish Diseases And Medicine For Treatment

It is of no doubt that appropriate Feed and fish feeding is one of the Secrets of fish farming business that can improve your revenue. Another striking factor that determines how well you will do in catfish farming business is having a great knowledge on common fish diseases and their appropriate medicine.

Fish disease is any condition that impairs normal physiological functions of fishes which may require medicine or other actions to annul the changes. Fish disease outbreak increase production cost because of the investment lost in dead fish, the cost of treatment and decrease growth during convalescence. Therefore, the best way to ensure a healthy livestock is through disease prevention rather than the treatment itself.

Nevertheless, the most effective measure for disease prevention in aquatic life is through proper water management principles. In other words, good water management is equivalent to healthy fishes.

Factors that contributes to fish diseases

Infections diseases are caused by pathogenic organism present in the environment or carried by other fish e.g Parasitic, Bacterial, Viral and Fungal diseases. Parasites and bacteria may be of minimal significance under natural condition but can contribute to substantial problem when animals are crowded and stressed under culture condition.

While the non infectious diseases – are caused by environmental problem, nutritional deficiencies or genetic defects that may pose stress and diseases to the fishes. Some of these factors includes;

  • Ammonia intoxication
  • Malnutrition
  • High stocking densities
  • Stress
  • High pathogen load
  • Reduced oxygen level
  • Lack of proper water management
  • Transference of disease from another farm

Therefore, the management of the fish diseases or the type of medicine to uses solely depends on the etiological factors – Some may require just the change of water while others may require introduction of a particular drug.

Fish health management are designed to prevent fish disease once fish get sick, salvage may be difficult. Hence,
ability to recognize a disease condition in a fish population is essential for early detection and effective control.

Prevention of fish diseases

The popular saying, “prevention is better than cure” is also so much appreciated in fish farming business. In that regards, fish farmers are expected to take precautionary measures that will limit the spread of disease in his farm that will cause serious financial risks to his business.

Consequently, below are some measures to take to ensure that fish diseases is limited and prevented to its minimal level in a fish farm.

Fish Vaccination

Since the popularity of fish farming business, many fish diseases have emerged and therefore, the need for some vaccines to help fight some of these diseases.

Vaccination is a prophylactic measure that helps fishes develop immunity that will fight specific microorganisms which protects the farmer from associated cost that may arise from future treatment, death and having sick fishes in your farm. This simply means that vaccination is a proactive measure to save future costs.

However, challenges associated with vaccination is that in commercial farming, vaccination of a large school of fishes is difficult and time consuming. Also, vaccinating of small fishes less than 15g is difficult and may pose stress to fishes because of the tedious exercise.

There are three methods of fish vaccination which includes; Oral vaccination, injection and immersion method. fishes benefit more from injection method of vaccination, However, smaller fishes that can hardly be held benefit more from immersion method. 1

Fish Bath

A fish bath is a method that is employed for disinfection or to serve as an antiseptics to fishes. It can be used as a quarantine technique, for prophylaxis to prevent infection or as a treatment for already sick fishes. It is even recommended that before a proper treatment of fish or when not certain of the cause of the disease yet, the water should be changed and a bath is initiated.

Common therapeutic agents that can be used for fish bath are Normal saline or Epsom salt, copper sulphate, potassium permagnate and formalin.

However, attention should be paid to the calculation of the quantity to be used for each bath and duration of a bath.

Proper water management

As stated earlier, non infectious fish diseases are as a result of changes in the environment of the fishes. The fish environment as we know is the water. Consequently, the level of water management is synonymous to the quality of the fishes a farm produces.

Fish pond water management is basically focused on both the standard physical and chemical water properties of the fish pond. This is to ensure that the fish pond at every point in time maintains the optimum physical and chemical conditions that permits the thrive of the aqua life. So, farmers are to monitor these parameters occasionally in their farm.


Pond Water Chemical Properties

  • pH of water
  • Hardness of water
  • Dissolved gases: oxygen, carbon dioxide, nitrogen, ammonia
  • Salinity



Pond Water Physical Properties

  • Temperature
  • Turbidity
  • Smell


Also, attention should be paid to the type of feeding to avoid water contamination through overfeeding of fishes. Toxic gases released by unconsumed feeds such as ammonia, hydrogen sulphide and carbondioxide at a high concentration can lead to death of fishes due to suffocation within some hours.

Fish Quarantine

Fish quarantine means a method to isolate fishes from another farm for some time to examine and treat them from actual or potential diseases before putting them together with the other fishes in your farm. The minimum duration of fish quarantine should be at least 4 weeks, so that, the farm can ascertain the safety of the fishes.

Therefore, for precautionary measure, every farm should have a fish quarantine tank or bucket. An ideal tank does not have any special thing in particular, but should contain means of administering prophylactic medications or bath.

Proper feeding of fishes

Fish feeds and feeding should be adequate and meets the requirements of the basic daily nutritional requirements of the fishes. Proper feeding helps the fishes to stay healthy and to develop immunity to ward off infections.

With regards to proper Fish Feeds and Feeding Techniques, attention is paid to all the parameters of fish feeding which includes;

  • Frequency of feeding per day
  • Timing of feeding
  • Food rationing and quantity
  • Nutritional requirements of feeds
  • Effective feeding methods
  • Feed Conversion ratio
  • Types of feed etc.

Summarily, all farmers should know all those parameters to be able to give the fishes the best feed that can help them stay off from diseases.

Close observation to physiological changes of the fishes

One of the secrets of a successful fish farming business is for the farmer to take responsibility of knowing what goes on in his farm. In that regards, a good farmer is observant to look out for any striking irregularity or physiological abnormalities with the fishes. There are some features a farmer should look for to know that a fish is sick, here is a few list of them;

  • Change in body color
  • Presence of swellings or nodules on body
  • Erratic or sluggish swimming
  • Emaciation
  • Death rates
  • Skeletal deformities
  • Presence of hemorrhagic spots on the body and so on.

Once you spot any of the above features in your farm, the best thing to do is to segregate the affected ones to avoid spread till they are fit to join others.

Common Fish Diseases and Medicine

In the fish farm, there are common fish diseases that pose threat to the morbidity and mortality of the fishes. The medicine below can be used in your farm when you notice the following signs/symptoms in your fishes.

In the table below are the common diseases, symptoms and the medicine used for treatment.




Parasitic Infection

(i) Tapeworm e.g
Corallobithrium finbriatum

There may be no outward indication but fish may lose
weight or become sterile.

• Avoid maintaining or purchasing infected fry.
• Drain, dry and disinfect ponds after each harvesting
• No therapeutic agent

(ii) Ich or white spot disease

• Small raised spots over the entire body surface and fins.
• Heavily infected fish often
congregate at the intake or outlet of pond.

• Avoid contaminated water supply nets and other equipment.
• Provide good water and balanced feed.
• formalin table salt copper sulphate and potassium
permanganate can be used as therapeutic agent.

(iii) Fish lice

• Infected Fish WillFlash Or Rub Against Tanks
• Show red spots

• Stocking of parasite for fish
• Masoten (Dylox) can be
used as therapeutic agent


 (i) Saprolegenia and

• Fish have general cotton- like appearance associated with discolored area or lesions.
• Fungus assumes the colour of material suspended in the  water.

• Maintain good water quality and nutritionally adequate feeds.
• copper sulphate, potassium
permanganate, or formalin can be used.


(i) Bactermia
(Haemorrhagic septicemia)

• Shallow, irregular, margined reddish sores on sides.
• Pop eye
• Enlarged fluid filled belly.
• A reddened area around the anus.

• Avoid overcrowding and rough handling.
• Provide good water quality and feed well fortified with vitamin C.
• Oxytetracyline addition to diet is therapeutic

(ii) Columnaris

• Discolored patches and scale loss.
• Mouth and barbell erosion, fin erosion, tail erosion
• 30- 70% mortality

Treatment of water with KMn04
• Medication of feed with


(i) Broken back diseases
(ii) Broken head diseases
(iii) No blood diseases

Deformation of spinal cord
Crack on the head
Fish become anaemic and die

Fortify feed with vitamin C
Vitamin C and bone meal
added to feed
Folic acid which is added to
new feed after the old one as

Methods of fish drug administration

The principle behind the treatment of fishes is similar to those of other animals, However, their habitat which is a fluid medium poses some challenges to effective administration of  drugs. The route of drug administration for fishes is as important as the medicine itself.

There are basically three methods of fish drug administration. and each method has its advantages and disadvantages and the choice depends on the goal of therapy.

Oral route of drug administration

The oral route simply means the type of drug administration where drugs are meant to be taken by the fishes through the mouth. In small farms, a farmer can choose to separate the sick fishes and give them drug directly in the mouth with the aid of a cathether. But, this process is tedious and time consuming in big farms. Hence, fish diseases can be treated by mixing of the medicine with the feed.

Medicated feed or the mixture of feed with drug sometimes have setbacks that limits their use in the farm. An idle sick fish looses interest in feeding, when the fishes are fed with medicated feeds, the healthy and powerful ones compete more for the feed while the sick ones that needs the food may not likely eat. Consequently,  the healthy ones takes overdose while the sick ones have under dose.

Therefore, it is not advised to use medicated feeds for drugs that have narrow therapeutic index (that are toxic with slight increase in dose) such as Antibiotics, unless they are being used as prophylaxis rather than treatment.

Administration by bath

The body surfaces and gills of fishes acts as a membrane for absorption and exchange of substances – drugs are one of these substances. In this method, the drug of choice is dissolved in the water medium and the fish is allowed to stay in the water for a period of time that will allow the absorption of the drug.

The administration of drug by bath is one of the most widely used type of administration because of its ease and lower cost. Moreover, since it has to be absorbed through body surfaces, fishes that can hardly feed can also benefit from this method. Also, smaller fishes that may be stressed by other methods of administration benefits more from this method.

On the other hand, the challenge associated with this type of drug administration is that most drugs are not soluble in water and sometimes calculation of the dose to use or duration maybe difficult.

Most commonly used medications by this method are the disinfectants such as Potassium permanganate, Formalin, Table salt and copper sulphate.

Parenteral administration

This method is by direct administration of drugs into the body of the fish with injections. It is one of the most effective method of drug administration but is common in small scale farms. In larger farms, it is always difficult to catch fishes and give them injection individually. Also, the fishes tends to be stressed during this period and can as well be a threat to the  health of the fishes.


Most fish diseases becomes hard to control when they spread in the farm, the use of medicine may not savage the damage already incurred. So, the mainstay of a healthy fish is to prevent the disease or limit the spread once you notice any sign of disease in your farm.

error: Content is protected !!
Scroll to Top