Every aquarist is familiar with the signs of Ich, Cryptocaryon irritans: white spots covering the surface of a fish that look like salt. These white spots are places where the Ich parasite, a ciliate, ahs burrowed beneath the surface of the skin of the fish to din on skin cells and blood it carves out of the flesh around it. While there have been folk cures for Ich that are “reef safe”, such as garlic, none of these truly effected a cure. Not only do they not kill the parasite on the fish, they do nothing for the parasite in the system, and the fish can become infected again. Now, thanks to the aquaculture and food fishery businesses, a new treatment for Ich has been reported that not only kills the ciliates on the fish, it kills Ich in the system in a reef safe manner. The cure? A combination of botanical extracts and some simple husbandry tricks.
Botanical extracts have been tested against Ich for years, particularly those derived from tropical plants, because most of the fisheries most affected are in southern Asia. Mango seeds, rosemary, coconut extract, and rotting mangrove leaves have all been tested, and all show some activity against Ich, but not enough to kill the parasites off completely. What researchers did differently this time is to use combinations of extracts, in the hope that they would work synergistically. After many trials (and many extracts), the combination of pineapple and coconut extracts was found to have the best activity against Ich. In trials, using 1.5% pineapple and 1.5% coconut extract killed 99% of the Ich bioload.
But of course, 99% isn’t good enough, because as soon as the extracts are washed out and the fish are rechallenged with new parasites, they succumb. Researchers found that to get a complete kill they had to chill the systems and drop salinity quickly for a brief period of time, bringing the temperature down at least 15°C over 10 minutes and allowing the systems to return to regular temperatures gradually. The quick way for doing this, they found, was to dump crushed ice in the system (crushed because it allowed greater surface area and quicker melting). Interestingly, the addition of a small amount of ethanol to the extract mixture also potentiated the immune system, allowing the fish to resist attack from other external parasites as well.
While there is no commercial product available, this anti-ich blend can easily be made by the average aquarist at home. Simply blend 2 oz pineapple juice with 2 oz crème of coconut (a store-bought stand-in for coconut extract), plus an ounce of ethanol-of choice, add enough ice to cool your tank, and run the whole thing in a blender to crush the ice. Once the ice is sufficiently broken up dump the entire thing into your system to kill off all the ich parasites. Reef-safe, easy to make, exactly what aquarists have been craving!