II. Treating Saltwater Ich

All too often fish, invertebrates, live rock and other organisms are not properly quarantined before being added to their new home, potentially introducing all kinds of opportunistic pathogens directly into the display tank. One particularly common disease is Cryptocaryon irritans, more commonly known as Marine or Saltwater Ich. If left untreated, this parasitic infestation can lead to other secondary opportunistic infections such as bacterial infections like fin rot, red patches, ulcerations, and ultimately death. This issue is particularly important for puffer keepers, as certain fish, such as tangs and puffers, are more susceptible to marine ich than others. This article aims to educate you on how to identify, treat and ultimately prevent Ich outbreaks in your saltwater tanks.

In order to understand the parasite, one must understand its life cycle. When one sees the actual white spots, one is seeing the adult form of the parasite, often referred to as trophonts. These cysts will mature, encapsulate themselves, and fall off of the fish to the substrate. The encapsulated cysts are now called tomonts. Tomonts will divide/multiply into small ciliated (hair-like) organisms. At this stage, they are called tomites. Tomites swarm the tank looking for new fish-hosts. Once found, they bore into the mucosa of the skin, fins, and gills, continuing their life as trophonts. The life cycle of the parasite is now complete. This process takes several days, meaning that hobbyists will often see spots “come and go” depending on which point in the life cycle the parasite is in. Even when the spots are not present, the ich is still there, and has merely entered a new phase of the life cycle.

Symptoms other than white spots you can use to identify Ich include:

  • Scratching and erratic or frantic swimming due to the fish trying to rid itself of the boring pest.
  • Rapid or heavy breathing, with the fish tending to stay at the water surface, close to water return pipes or powerheads, or in airstone bubbles due to parasites in gills affecting respiration.
  • Increased mucus production (slime).
  • Eye cloudiness (especially with puffers).

All too often you will hear, “My fish was doing fine for a couple of weeks and all of a sudden white spots appeared.” The spots can often appear after a stressor, such as a sudden change in tank chemistry (i.e., fluctuations in pH, alkalinity, ammonia, Oxidation-Reduction Potential (ORP), temperature, etc), after a new tankmate has been added, after mating or courtship behavior, or after disruptive tank cleaning or redecoration.

Chronic stress is a stress that persists for a prolonged period of time (i.e., days, weeks, or months), but does not acutely cause behavioral changes in the fish. Examples of this would be chronic suboptimal water quality (chronic low oxygen levels, ORP or pH), inappropriate or tainted/spoiled food, unwitnessed aggressive tendencies or inappropriate tank mates. These chronic conditions put strain on the fish’s immune system, meaning that where it was once able to fight off the pathogen or parasite, it has now becomes infected.

If the fish has a strong immune system, they have a slight chance of overcoming the infestation, but I’m not a betting person, so don’t ask me to place odds or chances. With that being said, the constant presence and reinfection of the parasite until (if ever) the fish develops an immunity/resistance, can cause chronic stress, increasing the chance that the fish may fall victim to secondary bacterial, fungal or worm infestations. Adding new fish to this system at this point, even if they have now been properly quarantined, is risky, as they too will be exposed and become infected.

How to rid the tank of the parasite:

The preferred method of ridding the parasite is achieved by removing ALL of the fish from the main display tank and placing them in a separate, bare-bottom quarantine tank for a minimum of 4 weeks, though 8 weeks is preferred. The tank will have to remain fallow (fishless) for the entire time. By removing the fish, the parasite does not have a host in which to complete its life cycle and will eventually die off completely.

Another option would be to treat the main tank with copper. I do not recommend this method, especially in a reef system, one with live rock, or substrate. Copper will KILL inverts, corals and the micro fauna on the live rock. Furthermore, the substrate will leach/absorb the copper and the therapeutic treatment levels needed to cure/rid the parasite will not be achieved.

There are many ich cures marketed as “reef safe” – I do not recommend them. If you visit enough sites and talk to enough hobbyists, you will find those that highly recommend these products and then others that have had miserable or disastrous results….this is true about every aspect of life and science. I do not gamble when it comes to the life of an animal, fish or human.

What to do for the fish:

Note: All fish must be treated in a separate quarantine/hospital tank.

  • The parasite requires saltwater conditions to survive, therefore, by lowering the salinity the parasites will die off. This is called hyposalinity, and requires obtaining a Specific Gravity of 1.009 (measured with a refractometer or hydrometer at least daily) for a minimum of 4 weeks.
  • The tank needs to be bare bottom (no substrate) with hiding spots for the fish. Hiding spots should be things that can be sterilized after each use – pvc pipe/couplings or those plastic caves/decorations used in freshwater tanks.
  • There should be some source of biological filtration. I prefer air driven sponge filters that can be cycled or maintained in your display system’s sump or a sponge or bioballs in a hang-on-back filter. Both of these can be quickly removed from the display system and added to the quarantine tank when needed.
  • Additional aeration (air stone or power head pointed from the bottom of the tank to surface) will also be needed to meet the fishes increased demand for oxygen.
  • Another option is to treat the quarantine/hospital tank with copper. Copper has been proven as an affective treatment for Ich. However, Copper is also an irritant and fish breeders have found it to affect fertility. Furthermore, Copper kills inverts, algae, and corals. Some fish (scale-less fish, elasmobranchs) are very sensitive to copper and do not do well. If you use copper, in addition to the other water parameters, you must monitor the copper levels daily to prevent toxicity (high levels) as well as subtherapeutic levels (low levels) as both extremes will affect the outcome/cure.

Whether you choose hyposalinity or copper treatment, you must monitor the water parameters in the tank at least daily, as pH, ammonia and nitrite levels can change rapidly. This causes additional stress which can affect the success of the cure. Frequent water changes and the addition of buffer to maintain pH are required. Improving the fish’s immune system will also help. You can do this by the addition of beta glucan, vitamins and garlic to the fish’s diet while in treatment.

Watch closely for secondary infections as mentioned above. Antibiotics may need to be added. I would not recommend treating with antibiotics prophylactically or “just in case” as this can add stress or lead to drug resistant pathogens.

If you don’t like these proven methods of cure, the only other option is to break down the tank and start over. So the best possible advice is to quarantine everything to begin with, you won’t regret it!

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