Monday, October 4, 2010

Ich Attack

A tang with Ich.

It's been a bad week for our aquarium. Almost immediately after the loss of Phillip, we noticed white spots covering the fins and body of both Chantal, our Blue Tang ( and Elton, our Helfrichi Firefish Goby( Chantal had already been somewhat immunocompromised, fighting off what we think was lymphocystis. Elton had recently been introduced to the tank and may have brought the parasite in from the LFS. Regardless, both of these guys were already under a lot of stress, and that was before I dismantled the aquarium. This disaster must have added more stress to these guys because the ich outbreak was glaringly apparent almost immediately afterwards.

What is Ich?
Ich, or white spot disease, Cryptocaryan irritans, is a parasite that infects saltwater fish. Although there is another parasite called Ich that attacks freshwater fish and causes similar symptoms, it is a different parasite (the freshwater form is Ichthyophthirius multifiliis). Luckily, saltwater ich is slightly less aggressive than the freshwater form (which attacks the gills first and impairs breathing), making it fairly easy to treat if caught early. This parasite is a ciliated protozoan with a 28-day life cycle (making full treatment fairly prolonged).

After the parasite embeds into the mucous of the fish, it appears as white spots (small grains of salt) on body and fins. In the early stages, the fish remains asymptomatic, although you may spot it scratching on rocks and sand (called "flashing"). This is the best opportunity for treatment. As the infestation spreads, it later attacks the gills and impairs breathing. In the late stages of infection, the fish becomes listless, loses color, stops eating and swimming, and often succumbs to secondary bacterial infections. Death is the final outcome.

The best cure is, of course, prevention. Ich is often introduced into the aquarium via a new fish, coral, live rock, live food, or invertebrate (any outside source). Therefore, quarantining new specimans for a minimum of 10-days is a great idea.

Keep in mind that there is probably already ich in your aquarium. However, if your fish are healthy, they're immune system will ward off infection. If your fish are stressed, they will often get infections like ich due to a dampened immune system. Stress includes, introduction of new fish, aggression between tank mates, poor nutrition (not enough or not the right kind of food), overcrowding and poor water quality. Avoiding these problems should be the first goals of good aquarium husbandry.

When you spot a fish with ich, weigh the pros and cons of different treatment options. Removing him and putting him in a hospital tank allows you to treat him without killing your coral and live rock (as well as other invertebrates). This also prevents other fish from getting infected. Remember that treatment is most successful when done early on. On the other hand, ich sometimes goes away on its own if the fish is healthy enough to fight the infection. Frequent small feedings and water changes can help boost the immune system. Keep in mind that the more you handle the fish, the more you are stressing him, which can sometimes worsen the infection. There have been some rumors that garlic extract added to the diet helps the immune system but the evidence is anecdotal. However, it can't hurt (it won't hurt your corals or other inverts). I am actually currently trying this.

In addition, upon first spotting a sick fish, all water parameters should be tested to ensure that the aquarium is in good general health. Make sure your pH, temp, salinity, ammonia, nitrites, and nitrates are all within desired parameters.

The next step is to do a water change of 10-20%. This aids in removing the parasite from the water, lowering the concentration of the ich, improving water conditions, and making it unlikely that your other healthy fish will succumb as well. Remember, ich is contagious. You don't want to lose your entire tank.

There are several more aggressive treatment options for ich. Unfortunately, most of them cannot be done in a reef tank because the chemicals will kill the corals, shrimp, and nitrifying bacteria in the live rock. Perhaps the only one that might be considered is raising the temperature of the entire tank (s.l.o.w.l.y.) to 82-84 degrees. This speeds up the life cycle of the parasite and when combined with frequent water changes, can help get rid of ich. Less light in combination of this can also help interfere with the parasite's life cycle. Raising the temperature is the least effective and slowest treatment option for ich.

If you have a fish-only system, you have more options. Lowering the salinity to 1.015 will kill the parasite without harming the fish. Salinity should be lowered very slowly and maintained at the low level for about a month to completely kill off all parasites.

In a reef aquarium, a freshwater dip for no more than 4 minutes can be performed. Since ich cannot survive in freshwater, this is often a miracle cure for infected fish. However, keep in mind it's also very stressful. Be sure to match the pH and temperature to the main tank before starting. An ich treatment can be added for added effectiveness (containing formalin/methylene blue).

If you isolate your fish in a hospital tank, you can use hyposalinity for a month to kill ich. You can also increase the temperature to speed up the life cycle of the parasite. Be sure to do these changes slowly so as not to further shock the fish. In addition, the water can be treated with lots of "Ich" cures on the market. These include formalin, methylene blue, and copper. Be careful to follow instructions carefully as all of these chemicals are extremely toxic (to the fish and you). Unfortunately, I learned this the hard way (formalin robs the water of oxygen and can asphyxiate the fish). More on this in a later post. It's a sad day for our aquarium.

Links on Ich:


  1. I feel strongly that a dog heaven exists, and it follows there is a fish heaven too.
    Sorry about your losses.

  2. With your frequency of fish purchases it is probably a good idea to setup a quarantine tank, as Paletta suggests in his book. Your LFS apparently doesn't quarantine well the fish they sell.

  3. I agree. I've learned my lesson. Quarantine tank from now on. Plus, no more fish purchases!