Salt:
Salt is frequently recommended for treating a myriad of fish diseases, especially those involving external protozoa and fungi.
What kind of salt? We are not talking about “marine salt” or “cichlid salt” (both of which typically contain a blend of mineral salts and trace elements specially formulated for aquarium use to simulate ocean or rift lake water chemistry). You want sodium chloride (NaCl). “Aquarium salt” is the most widely used form because it does not contain the iodine or anti-caking agents that table salt does. I will say, however, that several credible sources assert that the minute amount of additives in table salt are harmless. Robert T. Ricketts, writing for AquaSource online magazine, puts it best with “any water-living vertebrate would be pickled in brine well before toxic concentrations of iodine could be reached.” Still, others offer strong warnings about the dangers of iodine and prussiate of soda (an anti-caking agent) and suggest “canning salt” as a cheaper alternative to aquarium salt. Make your own choice, but since I’ve heard only warnings and no actual accounts of fish death by table salt, I assume it’s most likely the ‘better safe than sorry’ principle at work here. “Sea salt” is another option, and is generally available in nutrition stores because it is considered a more “natural” form of salt. It does not contain iodine, but may have anti-caking agents. I have used it in my aquariums without incident.
Can my fish handle salt? I wrote this article with African rift lake cichlids in mind, and I have successfully exposed my Malawi haps and clown loaches to a salt treatment without any problems. But these fish are accustomed to fairly hard water with a high pH. It is my understanding that species preferring soft water will not tolerate salt as well. If you keep soft water fish, please do your homework before proceeding with salt.
How much? I visited websites and read articles on treating Ich in generic freshwater fish, food fish, guppies, loaches, and African rift lake cichlids to name a few. I encountered dosage recommendations ranging from about 1.75 tablespoons to 6 tablespoons salt per 5 gallons of water. One rift lake cichlid importer/breeder uses “1 handful” of salt per 5 gallons of water. I concluded that my fish can probably tolerate more salt than I think, at least on a short-term basis. Based on everything that I’ve read to date, I would feel comfortable adding 2-3 tablespoons salt per 5 gallons if I were also using the high temperature treatment outlined above. If I were using salt alone, I would work my way up to 4-5 tablespoons per 5 gallons. We don’t want to skimp on our treatment if we hope to permanently eliminate this pest. Salt should be added slowly over the course of 24-48 hours or so (always dissolve in a small container of tank water first). Keep a close eye on your fish and perform an immediate water change if they show any additional signs of stress (beyond what the Ich is already causing).
How long? The salt bath should be maintained for approximately 10 days, or for at least 3 days after any visible signs of Ich can be detected. Do not discontinue treatment when the spots go away. If you use a higher dosage of salt, watch the duration more closely. One article (on guppies) specifically stated not to leave the fish in salt longer than ten days, but their dosage recommendation was on the high end at 5 tablespoons per 5 gallons
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