I noticed that some people are not aware of the hyposalinity treatment for salwater ich. Some people are aware of it, but believe it is a "holistic" and bogus approach that does not actually work. If you have not heard of this treatment, let me tell you a bit about it. I found a great article explaining how and why it works. I've also reseached this principle in the past, and did a project demonstrating it. Check out the video-- its pretty neat to see. Hopefully I can spread awareness about this great alternative to ich medicines and save some fishy lives. The method I have used to successfully treat a lightly infected fish was to put it in a 10 gal quarantine tank, with a hang on back filter, an air-stone to prevent bacteria growth (though this is probably not necessary if you have a filter), a tank HEATER, and salt water. The equipment is mostly low-cost, and you probably have it lying around already. If not, check craigslist! Fill the tank with salt-water at 1.009 salinity. I adjusted mine until it was exactly this. Put your fish in. You can acclimate him if you like (though I didn't). Lowering the salinity will not harm the fish, though raising it quickly might. Set the heater in your quarantine tank to 88 degrees. The high temp inhibits the ability of the ich parasite to breed, and will not harm most fish. Leave him there for 2 weeks. At the end of that time, if he is completely ich-free, slowly begin raising the salinity so that at the end of the third week it matches that of your display tank. Then acclimate him to your display, and return him! If he still shows signs of ich, leave him there and be patient. The parasite will eventually cycle through its life stages and drop off, and it will die in its free-swimming form because of the low-salinity. I imagine this method will be most successful if you nip the ich in the bud! Examine your fish every day for signs of infection or abnormal behavior. Especially if you've added a new fish or if your water quality has not been up to par lately. Also, you can keep the Quarantine tank at this salinity and treat most of your incoming fish for ich whether its visible yet or not. I am not aware of any fish that woudl be harmed by the increased temp and lowered salinity, though I am sure there are some that are sensitive. Inverts probably are. Do your research before hand. For fish that are extremely covered in ich, this may not be enough. There are some more radical methods that may be worth mentioning if your fish is near death. These methods include total freshwater dip for a very short amount of time each day, in addition to low-salinity environment and quarantine. Ask me and I'll go into more depth about it. This is for emergencies only. Here is my video demonstrating bacterial susceptibility to environmental salinity changes: http://www.youtube.com/watch?v=ZLPOnhnbSic Here is the article explaining how it works. If you'd like a direct link to it or other similar articles, PM me (as I'm not sure I am allowed to post those link here). About Hyposalinity or Osmotic Shock Therapy A Simple, Effective, Non-Chemical Treatment for Ich By 66cc">Stan & Debbie Hauter What is hyposalinity? Hypo means "lower than normal", and saline/salinity "of or containing salt", therefore hyposalinity in the simpliest of terms is a lower amount of salt contained in seawater than normal. With the salinity level of oceans and seas around the world averaging out at around 1.024 (specific gravity), although lowering the amount of salt in water by a few points might be called hyposalinity, when it comes to saltwater aquariums this means bringing the salt content down to a range of 1.013 to 1.010 (specific gravity) to be effective and truly considered as such. How does hyposalinity effect ich and other marine organisms? All marine creatures require freshwater just as we do to survive, they just process it differently. Since their bodies are less salty than the water surrounding them, to prevent the loss of needed freshwater they take in seawater, process it to eliminate the salt molecules, and then retain the freshwater to maintain a balance with nature. When the salinity of seawater is lowered, or hyposalinity is applied, it results in a lowering of the osmotic pressure of the water at the same time, thus the related name Osmotic Shock Therapy (OST). Fish and a few other sea creatures can withstand and adjust to this change in pressure, but protozoan (Cryptocaryon/White Spot Disease, and Brooklynella/Clownfish Disease), dinoflagellate (Oodinium/Velvet or Coral Fish Disease), and flat worm (Black Spot Disease) ich organisms cannot. Reduce this necessary pressure, particularly rapidly, and they literally explode! Although delicate corals and invertebrates may not immediately rupture as ich parasites do, these too are marine animals that cannot tolerate exposure to low osmotic pressure, resulting in a rather quick death. When is hyposalinity most effective on ich? Hyposalinity is largely ineffective on mature ich parasites that are well protected in the gills surrounded by thick mucus produced by an infected fish, when embedded deep in the tissues of their host, and during the final encrusted cyst stage of life. It is primarily during the free-swimming phase of life when newborn organisms are released from a mature cyst, and before they have the chance to fully attach and develop into mature parasites that they are most vulnerable and can be eliminated with hyposalinity. When can this method of treatment be used? Applying hyposalinity or osmotic shock therapy to treat ich problems is a personal choice decision one has to make, but here are many of the ways it can be used. For a QT While treating fish in a QT, lowering the salinity can help prevent newborn ich organisms that might be released from mature cysts from reinfecting the fish during the quarantine period. As a preventative measure, when new fish are brought home and placed in a QT for several weeks of observation before introducing them into the main aquarium. For Fish-Only Tanks (Note: Under the following situations it is recommended to at least remove and give all exposed fish a freshwater dip, preferably in combination with at least a one time appropriate medication treatment before placing the fish back into the main aquarium, at which point the salinity is lowered for 3 to 4 weeks.)When a QT is not available, or the choice is made not to treat ich infected fish in one.When one does not want to leave their aquarium empty with no fish to look at for month. [*]When there is concern or one wants to lessen the possibility of reinfestation occurring after the fish have been treated in a QT and returned to the main aquarium. [*] When reinfestation does occur after the fish have been treated and returned to the main aquarium. For Reef Tanks Hyposalinity should NEVER be used in a reef system, as it will kill corals and all types of delicate invertebrates. Since most people in all likelihood will not want to disturb these animals, not to mention have to hassle with removing them and set up another tank to put them in, the easiest thing to do for a reef tank is to leave it devoid of all fish for at least 4 weeks and allow the ich to run its life cycle and die off. I welcome any comments, corrections, discussions, or supporting or disclaiming research/articles/personal experience. Just be careful not to link to sites that sell fish and I think you should be fine.