45. FISH DISEASES 



It is almost safe to say that there is no reliable remedy for a sick fish, no matter what 

 the cause. Prevention is all important for really there is no cure! However, there are 

 several simple rules to keep in mind: 



1. Never add new fish to an old aquarium until they have been sterilized and have 

 been quarantined for a few days. All new fish should be given a salt treatment, 

 regardless of their source. 



2. Provide separate aquaria for sick fish and isolate them as soon as there is any 

 indication of trouble. 



3. When shipping large numbers of fish it is said that mortality will be reduced if 

 a small amount of aspirin is added to the water (reasons unknown). (See 

 McFarland '60) 



4. When sick fish are found in a regular aquarium, this aquarium should be put 

 through a thorough process of cleaning and sterilization. Fish diseases are gen- 

 erally very contagious (for the fish!). 



5. Overcrowding and overfeeding are probably the second and third most frequent 

 causes of illness, the first being parasitization. 



6. The chlorine in drinking (tap) water is a good bactericidal for human beings but 

 harmful to the fish. Chlorine will naturally evaporate from standing water if 

 there is sufficient exposed surface, but warming or agitating the water will hasten 

 the process. (See Cple and Lewis 1958) 



Some fanciers recommend a tonic salt bath for all fish once each month. Such a bath is 

 made by adding 3/4 teaspoonful of NaCl and 1/4 teaspoonful of Epsom Salts (Mg^SO^) to 

 a gallon of boiled and cooled tap water. The fish may be left in this for 24 hours. If the 

 fish are definitely sick, the dose should be increased by using only one quart of water 

 and expose them for 1/2 hour, or less if they indicate intolerance of the treatment. 



Nigrelli (1961) has made a thorough analysis of the diseases (and other causes of death) 

 of marine, temperate, and tropical fish. Some of the parasitic, and infectious diseases 

 and other causes of death he lists are: 



Parasitic and infectious diseases . 

 Diseases of the skin and gills: 



Saprolegnia (fungus) 



Tuberculosis 



Ichthyophthirius (a Ciliate) commonly called "Ich". 



Gyrodactylids (a Trematode) 

 Diseases of the circulatory organs: 



Ruptured sinus venosus (due to Gordiid worms). 

 Diseases of (general) internal organs: 



Mechanical destruction (by Gordiid worms). 



Non-parasitic and non-infectious diseases. 



Diseases of the digestive system: Diseases of the skeleton and organs of 



Liver degeneration locomotion: 



Biliary cirrhosis Swim bladder trouble 



Diseases of the reproductive organs: Lordosis 



Egg bound Diseases due to nutrition: 



Ovarian degeneration Malnutrition 



351 



