take it out in half an hour. Repeat this procedure daily if neces- 

 sary. Goldfishes and native fishes respond well to this concentrated 

 salt treatment, but it may prove to be too drastic for rare exotics. 



FOR FUNGUS 

 Fungus is a slimy or hairy growth over the scales, fins, or mouth 

 of a fish, and usually marks the site of an injury. The treatments 

 are various. The fish may be lifted out of the water very gently 

 and the place swabbed with 2 per cent mercurochrome, 5 per cent 

 methylene blue, or a cherry red solution of potassium perman- 

 ganate in water. Be sure not to get permanganate on the gills. 

 Permanganate should be a last resort for exotics, for many seem 

 to be very sensitive to it. 



FOR EXTERNAL PARASITES 

 One of the most common animal parasites of aquarium fishes is 

 the protozoan parasite Ichthyophthirius viultijiVms, which lives up 

 to its long name by being a rapidly multiplying skin parasite. An 

 infested fish will droop listlessly, and tiny, milky specks that look 

 like sand grains can be seen covering it, especially on the fins and 

 gills. In a few days the adult parasites drop off, each giving rise to 

 a swarm of progeny. Each adult leaves a raw, bleeding spot on the 

 fish. After some days of this infestation the fish dies. In the case 

 of cold water fish, enough potassium permanganate can be added 

 to the aquarium barely to tinge the water with pink. This treat- 

 ment should be repeated about twice a week, or until all symptoms 

 disappear. 



Exotic fishes suffering from Ichthyophthirius, frequently called 

 "the itch," as the fish try to scrape off the parasites, are best treated 

 with mercurochrome or methylene blue. Three drops of 2 per cent 

 mercurochrome per gallon of water, or two drops of 5 per cent 

 methylene blue per gallon, will usually effect a cure. The water of 

 the aquarium containing the infested fish is treated. At the same 

 time the temperature is kept not lower than 75° F. After two 

 weeks, the treated water should be replaced. 



Sometimes parasitic worms will be seen on the gills and on or in 

 the skin of fishes, especially goldfishes. If possible, pick them off 



[102} 



