ICH Disease on Fish

Disclaimer: I don’t consider myself a fish expert, however I have had fish throughout my life, and I am willing to share with you the issues and bouts I’ve had how I managed/treated the situation(s). I am also including methods and information from other resources (listed at the bottom of this article) that I have used or found helpful or worth remembering/documenting. Please feel free to try the remedies I’ve used myself, however because there is no way for me to know all of the details about your fish or the tank/environment they live in and recent activities or stresses the fish may have encountered; I can’t guarantee the end results you may encounter.

What is Ich?

Ich/Ick, Ichthyophthirius multifiliis, is an external parasite commonly found in aquariums. Most fish keepers will experience an ich infection within their first 6 months of their tank being set up. As with many illnesses, Ich can’t infect healthy and/or fish that are not stressed, which means if you have an Ich infection, there is something that is stressing out your fish. This also means that not all of the fish in your tank will come down with Ich, only those that are stressed. What can possibly stress out a fish you might ask…

  • a change of habitat or a disturbance in routine and behavior are able to cause stress.
  • water quality or a water parameter (such as pH, temp, or a sudden change in either). Note: poor water quality can lead to swim bladder disease. High ammonia or nitrate levels, low oxygen levels, improper temperature or a high or low pH can cause stress.
  • A bully fish in the tank. To determine “the bully”; if possible, watch your fish closely- if you see a fish chasing the another in the tank- that’s your bully. Not all fish will be stressed by this action, however like people, some are more sensitive than others. This often happens when there are only a few fish in a tank as the bully will tend to pick on the most timid in the tank. You can remedy this by adding fish or getting rid of the bully if it continues. Note: when it’s time for the fish to mate, the male will pick on the female(s) relentlessly, which is established breeding school has one male and four-five females so the mail doesn’t bully a single female to death.
  • chasing your fish around with the net. I’ve seen this over and over in videos on the internet- people acting like they’re digging for clams in the tank- shove that net in and quickly jerk it around until you net a fish or two. Put yourself in the fish’s place- wouldn’t that scare the crap out of you?
  • an opened wound

Signs of Stressed fish:

  • When stressed, often fish won’t eat,
  • fishing can develop odd swimming patterns when stressed, ie swimming frantically without going anywhere, rubbing on gravel or rocks, crashing at the bottom of or side of the tank,
  • locking fins at it’s side,
  • laying listlessly at the bottom of the tank floor,
  • gasping their mouth at the surface; a sign of poor water conditions (usually lack of oxygen) that will cause stress.

The Life Cycle of Ich:

The life cycle is highly depending to water temperatures; the entire life cycle takes from approximately 7 days at 77F degrees to 8 weeks at 43F degrees.

  1. Trophonts: This is the parasitic/feeding stage stage, lasing from 3 -7 days.
  2. Mature trophonts: At this stage, the parasites drop off the fish, usually up to 18 hours,
  3. Encystment: This is an encapsulated dividing stage. It will divide up to 10 times by binary fussion (it divides in order to reproduce; each divided part will regenerate itself to become a complete cell. }
    The tiny new infant parasites will break out of the cyst as a free-swimming parasite, each looking for a host. If they don’t find one within 24 hours, they will die.
  4. Tomonts: This is the reproductive stage (binary fission produces tomites), averaging 3-28 days.
  5. Tomites excyst: The parasite becomes theronts, which is the infective stage and…
    the cycle the repeats itself.

Ich in Hobby Tanks vs. Aquaponic Tanks:

For those with smaller, hobby fish tanks that are enjoyed in the home with ornamental fish, ich is relatively easy to prevent and very easy and inexpensive to treat. The the keeper of an Aquaponics system, this isn’t necessarily true or the same.

To compare differences, I will format this blog post showing for “Hobby Tanks” and “AQ Tanks”.


Hobby and Aquaponic Tanks:

  • Ich is easily to spot on your fish. It looks like tiny white fuzz balls, or some identify it as looking like grains of salt. Sometimes the spots can be larger and clumped together, looking line one larger spot. These spots usually appear on the body and gills; in the last case of ich I experienced, I first noticed it on my fish’s lip.
  • Fish ‘flicking’. This is when a fish will dart about the tank, often quickly flicking it’s side against the bottom of the tank. At this stage, the fish has progressed leaving the fish irritated. The flicking action is their way of trying to scratch against either the side or bottom of the tank.
  • The fish may produce excess mucus because of the irritation.
  • There may be loss of skin and ulcers from bacterial infections invading the wounds from the ich; most of the damage is caused when penetrating and leaving the tissue of the fish.



Hobby Tanks:

  • Keep in mind that the ich infection may have been triggered by something during a water change. Could be a sudden change in the water temperature  The stress weakens the immune system which allows the ich to infect the fish. Once the cause of the stress is removed, the immune system can usually get rid of the ich on its own. In most cases removing the stress is all that is needed. Hints to remove possible stressors:
    • If it appears to be a water quality problem:
      • if you haven’t changed the water recently, do so at a slow rate.
        • remove no more than 1/4 – 1/3 of the water in the tank.
        • use the fish tank water you removed from the tank to clean off the filter media, not fresh water.
        • replace the water with fresh water that is within 3 degrees of the tank water’s heat and that the pH is about the same. (Note: I have well water and don’t worry about the pH factor as it runs appx 8.0 pH; and have had no issues doing so in 4.5 years.)
      • if you have already changed the water recently, follow up with water changes, but do it more frequently as they are being cured;  Extra water changes are a good idea when anything is wrong, especially when it comes to treating Ich. Unless there is something about your water changes that is stressing the fish,  they will only help. Change the water every 1-3 days, replacing the same amount of water – in this case, more is not better.
    • If  you notice a fish aggressively chasing any of the other fish, remove it from the tank.
  • I have read from several sources that Ich can only infect fish who’s immune system is already compromised; primary by stress. It is not a communicable disease where every fish in the tank with get it simply by sharing the same water. With that being said, and with the fact that we are talking about a smaller fish tank, I would personally leave the fish altogether and treat them accordingly in their tank size.

Aquaponic Tanks:

Treatment is a little more involved with Aquaponic Tanks, primarily due to the size of the tank.  If possible, I would suggest identifying those fish that are obviously infected with Ich and place them in a smaller tank; 20-30 gallons.
It is best to relocate fish to a smaller tank for the following reasons:

  • it is less expensive to treat a smaller tank than a large one,
  • assuming the tank where the Ick was found is located is part of your existing AQ system, I would relocate all 0f the fish to a separate tank from the system; without fish to feed on, the Ich will die off after it has completed it’s life cycle; which is approximately 7 days assuming you keep your water temperature at 77°F or it can take as long as 8 weeks if the water temperature is kept at 43°F .
  • with the fish being treated outside of the AQ system, you can:
    • use the salt method
      • Salt treatments are very effective agains Ich:
        • Start out with 1/2 of a dose ( 1/2 Tbl per 2.5 gallons); put in the other half dose after about 12 hours.
        • Note: in most cases there is no issues using salt, but once in a while a fish may have a bad reaction to it (I have personally never had this problem.) Symptons: they may breathe more rapidly, clamp their fins or become lethargic. If this happens, do a water change to remove some of the salt.  Live bearers (ie Tilapia) react very well to salt treatments.
        • You will need to dose for salt again after each water change. So if you have a full dose of salt and then do a 25% water change then you need to add a full dose of salt for the 25% you changed. So if you have a 20 gallon and do a five gallon water change you need to add a full dose of salt for those five gallons, one tablespoon.
    • raise the heat in the tank
    • use a UV Sterilizer.
  • NEVER ever:
    • use UV sterilizer in a fish tank that is connected to your AQ system as you will kill both the good and bacteria that is need to cycle the ammonia to Nitrite to Nitrate, which runs the entire system.
    • add salt to your  AQ system  (most plants you are growing in your AQ system will not like the salted water and you may lose them.)

Hobby Tanks:

Garlic can be a very effective treatment against external parasites. I have seen cases of it being used against marine ich (unrelated to freshwater ich, but similar in appearance) in reef tanks where chemical treatments are not an option. I have seen New Life Spectrum Thera+A work to treat ich because it has so much garlic in it. In general food soaked in freshly pressed garlic is the best method because it is freshly pressed garlic that is most effective against parasites. Bottled garlic products sold at fish stores will not be effective against parasites. For more information about garlic please read: Garlic and its Ability to Kill Parasites

Hospital Tanks:
In my experience hospital tanks are not the best method of treatment. If one of your fish has ich they are all exposed, so isolating the visibly sick fish is not going to benefit the other fish. Hospital tanks are usually uncycled and smaller than the display so the water quality tends to crash very easily. Sticking an already stressed, sick fish into a smaller, uncycled tank is asking for a crash and more problems. In my experience leaving the fish in the display tank is a lot less stressful on them which leads to a faster, easier recovery. For more information about Hospital/Quarantine tanks please read: Quarantine: More Harm Than Good?

Raising the Temperature:
Raising the temperature is also a very common way to help get rid of ich. The idea is that is speeds up the progression of the whole progress. So as you start to do the right things to get rid of the ich, the higher temperature helps push the ich through its life cycle and get the fish over the infection faster. Raising the temperature up to about 82F in most cases is ideal.

Fish That Are Very Prone to Ich:
There are some species that seem to be especially prone to ich, what some people call “ich magnets” because it seems they can’t help but to get ich. These fish include: clown loaches, pictus/pimodella catfish (Pimelodus spp.), silver dollars, and many small tetras such as neons, cardinals, etc. When purchasing these fish it is a good idea to take a close look at the fish you are buying as well as all the other fish in the tank. However, although these fish are very prone to ich (they can be perfectly healthy and break out just from a cool water change), any fish can get ich. It doesn’t matter if they have no scales, small scales, are large, hard, plate-like scales. So be careful and be aware with any type of fish.

A Demonstration of the Connection Between Ich and Stress:
Many people think of ich as being infectious and that its presence is all that is needed for an outbreak. This couldn’t be further from the truth. Ich CAN NOT infect healthy, unstressed fish. The fish must be stressed. You may not be able to figure out what the stressor was, but it was there, at least at some point.

An experience I had demonstrates this perfectly. We got in a couple flagtail prochilodus at the shop I was running. I picked them out at the wholesaler, they were fine and so were the others in the tank. Shortly after getting to the store they broke out in ich. I did the usual treatment but after a few days they weren’t getting better. I wanted to take them home for myself since they are one of my favorites and they are only available a couple times per year. I started to realize that the tank they were in just wasn’t ideal for them. It was a sales tank, it was too clean. There was no algae for them to graze on. It was a little too well maintained. I decided that my 150 was probably a better home for them. I don’t mind algae on the decor or the back wall. It was also more fully decorated (you can’t chase fish around a sales tank full of rocks and driftwood, just a few pieces that are easy to pull out at the most). So I bought them both and took them home. Sure enough within days of being in my tank they were much happier and more relaxed. They could graze, had more space, more decor, and it was more natural. Within a week they were completely void of ich. On their own, without an increased temp, salt, meds, or extra water changes, they got over it completely on their own. Once I removed the stressor (the less than ideal tank they were in) they got over it on their own. In addition, none of the other fish in the tank they were introduced to ever came down with ich at all.

I have also bought fish from tanks and systems that had other fish with ich. The fish I bought didn’t show signs but were obviously exposed. They never came down with ich and neither did any other fish in the tanks I put them in. In these cases I made sure the fish I bought were healthy, not only showing no signs of ich but also alert, active, erect fins, etc. These fish were doing well and were not stressed even though other fish in the system were. This showed they were hardy and adaptable, not easily bothered. Those are the fish I want.

I am not recommending that you go out and buy ich infested fish. These examples are only given to show how strong the association is between ich and stress.