How to Treat Ich on Fish – Get Rid of This Harmful Encounter

Everything was going happily, and one morning suddenly, you noticed white spots on a fish’s body! And after carefully watching, you identified several victims. Probably this is just ich.

It’s not a terrible disease that can be acutely life-threatening, but a nasty infection, in fact. In the long run, it will kill your fish if left untreated.

Today I’ll talk about identifying and treating ich. But, I am not a vet, so this article is basically an experience sharing rather than a treatment guide. I’ll share my real-life experience about how to treat ‘ich’ on fish.

What is Ich?

Ich is a common disease of aquarium fish. A parasite called Ichthyophthirius multifiliis (ich in short) causes this disease.

It appears on fins, grills, and ultimately the entire body of the fish. If not treated timely, ich can turn severe and become deadly.

The parasite actually remains present inside almost all aquariums. If you can maintain a clean aquarium environment and fish’s good health, it is less likely that ich will infect the aquarium inhabitants.

How Does Ich Get Inside an Aquarium?

Ich is versatile in spreading themselves. They can enter your aquarium through new fish, invertebrates, plants, decors, water, or even maintenance equipment.

Buying New Fish/Invertebrates/Plants

New fish can carry ich and other pathogens. So I always suggest having a quarantine tank to isolate new fish for a period.

Similarly, newly bought invertebrates or plants should take under the disinfection process in a quarantine tank.

Not Washing Substrate Materials After Buying

Gravel or sand can carry germs of ich. So it is better to wash them thoroughly after you buy them. Boiling bottom matters in hot water before putting them in the tank is the best practice to eliminate germs carried by gravels and sands.

Using Shared Maintenance Tool

If you share tools like fishnet or gravel vacuum used in other tanks, they can bring ich to your tank. So, it is better to use dedicated tools for each aquarium.

It’s Always in Your Tank

Some aquarists believe no matter how you take preventive measures, ich will enter the aquarium. Somehow it manages to stay inside an aquarium.

Luckily it’s a treatable disease. If you can identify the symptoms early and ensure proper remedies, your fish will recover fully.

Lifecycle of Ich

To combat an enemy, you have to know it well. Ich is a real small foe for your fish and cannot be seen without a microscope. But, you don’t need a microscope to identify their presence, as symptoms are clearly visible by naked eyes. But definitely, you have to have some idea about it.

Ichthyophthirius multifiliis

Parasite Stage

In this stage, ich burrows into fish’s flesh. The parasite causes wound in fish’s body. The internal immune mechanism of fish becomes active and tries to protect its owner. So, a crusty white wall forms to seal itch in it. That is the primary symptom you see as white spots.

Due to the white scab, itch remains protected from external medication in this stage. But you have to start the treatment as soon as you identify any symptoms.

Intermediate Stage

In this stage, the white crust bursts out, and ich starts floating in the aquarium water. They are actually searching for a hard surface to attach to. (Probably, they will find the substrate as an ideal place for it.)

As the white scab ruptures, the cover of the fish’s wound falls off to make open wounds. This stage is critical for your fish as they are susceptible to fungal and bacterial infection with open wounds. Having more than one disease at a time can be really dangerous!

Reproductive Stage

Once got a hard surface as shelter, itch seals itself in an egg. By its own reproduction mechanism, ich divides itself into thousands of babies (theronts) inside an egg.

The egg protects the babies inside it from external enemies by its hard shell, including any medication. So, medicine won’t work in this stage also.

Transmissible Stage

This is the most critical time of ich and the perfect time for you to hunt enemies! Egg hatches, and baby ich becomes free in the water. They swim, searching for a fish body to burrow and house.

Baby ich is vulnerable to medication, and perfect treatment can make an end to their lifecycle.

Temperature and Lifecycle of Ich

The lifecycle of ich greatly depends upon the tank temperature. The higher the temperature, the shorter their lifespan is. 

The usual duration of their lifecycle in different temperatures is noted below;

  • 70˚F (21˚C) – Up to 18 days
  • 78˚F (25.5˚C) – Up to 12 days
  • 85˚F (29˚C) – Up to 6 days

Maintaining a higher temperature will make your fish less prone to ich. In a later section, I’ll discuss it in detail.

How Do You Identify Ich?

Most aquarists can identify ich by the common symptom – white spots on the body. It starts with a single spot. But a single spot is difficult to identify and not a clear indication of ich. Some fungal and bacterial infection initiates with white spot.

ich stage 1

As time goes, the infection spreads, a more white spot appears, and it looks like white salt sprinkled over fish’s bodies. Then you know, it’s undoubtedly ich.

In later stages, the white spots grow to larger patches. You may notice white spots on clear fins in this stage. In some cases, the spots appear on the fins before the body. Ich spots on colored fins are difficult to identify and may remain unnoticed.

ich stage 3

But the worst thing happens if ich attacks fish’s grills and mouths instead of skin or fins. It is very difficult to identify, especially if you have no previous experience battling ich.

Other symptoms in fish’s behavior are the indication of ich on grills and mouths. If grills are infected, fish will suffer from breathing difficulty. You’ll notice the faster movement of grills, and your fish will swim near the water surface.

ich final stage

As they are struggling to get adequate oxygen, fish start gasping for air. Gradually they become slow and lethargic in movement.

Ich becomes itchy for your fish. But they don’t have hands to give a good scratch. So you may observe fish brushing their bodies against any hard surface. Thus fish injure themselves, and wounds appear on their body. This is another indication that your fish are suffering from ich.

How Can You Treat Ich?

If you can identify the early symptom of ich, it is fully curable. I’ll suggest you treating ich with a few simple steps. This sharing is my own experience-based learning. If the infection has already gone too far, I’ll recommend consulting a vet.

Change Half of the Water

The first thing you have to do is changing 50% of the tank water. Adding freshwater will eliminate a portion of the free-floating parasites. So why only half? If you change all the water, it will eliminate more parasites, right?

But water changes can also hamper the nitrogen cycle and raise the concentration of ammonia and nitrite. You cannot take that risk, especially in such a vulnerable condition when your fish are sick and weak.

Raise The Aquarium Temperature

As I discussed the life cycle of ich, you realized a narrow window for effective medication. So, after a water change, slowly raise the aquarium temperature. 

At higher temperatures, ich (Ichthyophthirius multifiliis) has a shorter life cycle, so you’ll get the benefit of reaching the enemy’s weak zone quickly.

86˚F (30˚C) is the perfect temperature for an effective medication against ich. But you need to raise the temperature very slowly. Increase only 2˚F each hour. 

Sudden temperature changes can be deadly for fish as they are sensitive to thermal shock. In the case of heat-sensitive fish like goldfish, don’t go beyond 80˚F.

Another side effect of raising the tank water temperature is, it will lower the dissolved oxygen level. If you have a highly stocked tank without a proper aeration system, raising temperature can cause asphyxiation of fish. 

If you are doubtful about the consequence of raising the temperature, skip it. Still, you can fight ich. It will take just a little longer.  

Feed Them Garlic

Loss of appetite is a common symptom of ich, and your sick fish can refuse to eat their regular feed. It’s not a good thing to happen as sick fish become weaker. They lose their energy to fight disease. 

I’ll suggest a natural appetite stimulator; garlic. Garlic and garlic-based food are quite useful in making unwilling fish eat again. 

You can make your own homemade garlic infusion with a few steps. It will take some effort and time but saves your money.

  • Take a medium-sized bulb of garlic and peel it.
  • Cut the end of each clove and microwave it for 10-15 seconds. 
  • Cut and split the cloves into thin pieces. 
  • Put the strips in a cup of drinkable water. 
  • Keep it at room temperature for 24 hours, and the solution will be ready. 

You’ll have to soak your regular fish feed in this solution before feeding. This remedy is effective at the primary stages of infection only. Alternatively, if you want to avoid the hassle of solution preparation, you can use a prepared solution like Garlic Guard

There are garlic-based foods available in the market. You can choose a suitable one. I can recommend ‘New Life Spectrum Thera A,’ which is a potent one. As they offer different pellet sizes, pick the appropriate size for your fish.

Keeping a healthy diet continuing is crucial when treating sick fish. It enhances the power of their internal immune system. Otherwise, they are less likely to overcome the battle.

Choose the Right Medicine

Raising the tank water temperature and feeding a healthy diet to your fish prepared the field to apply medication. Now go for it. I will suggest some medicines, but before that, keep some points in mind.

tips for ich medicine

1) Right Dosage Calculation

Never overdose the medicine. Many noobs make mistakes in calculating the right dosage. The medicine instruction is given based on water volume. The common mistake that people make is they consider in a 10-gallon tank, the remaining water volume is also 10 gallons. But this is wrong! You never keep your tank 100% full, do you? And again, there is the substrate and decors in it.

In general, you need to consider 80% of the tank’s capacity as the water volume to calculate medicine dosage. That means in a 10-gallon tank, typically, there are 8 gallons of water.

2) Avoid Partial Dosing

Don’t apply incomplete medication. You have to ensure finishing the full medicine dosage. Using a partial dosage will not cure your fish fully. Instead, it will strengthen the parasite fighting against the medication.

Before applying medicine to your aquarium, read the instruction to the letter and follow them strictly.

3) Remove Chemical Filter

Remove chemical filter media such as activated carbon before dosing medicine. Activated carbon and other chemical media soak up certain drugs making the treatment ineffective.

My Suggested Medication for Ich

I am suggesting three medicines for ich treatment. As I said before, I am not a certified vet, so I am sharing only my own personal experience.


This product contains a combination of malachite green and formalin, which is pretty effective in treating ich.

This product stains aquarium items and causes greenish coloration of the aquarium water. The best way to treat ich with this product is to take your fish to a quarantine tank and apply medication.

Follow the instruction of using this medicine, and perform one-third of the water changes before applying each dosage.

Seachem ParaGuard

This product is non-staining as it contains less amount of malachite green than other ich medicines. Still, Seachem ParaGuard is a potent one for this purpose.

This medicine can be applied to sensitive fish. You have to start with one-fourth of the full dosage and gradually increase it. Seachem ParaGurad can treat secondary infections caused by ich.

Aquarium Salt

Salt is a commonly used medication not only for ich but also for different types of fish wounds. Here I am suggesting a product of aquarium salt.

Though salt is somewhat effective in treating ich, it’s not the specific medication for this disease. However, salt isn’t equally useful for all kinds of fish species.

By identifying early symptoms of ich, you can apply salt, and it may be sufficient. But, loaches, koi, and other livebearers are sensitive to salt. So salt is better to avoid if you are keeping these species.

How Dangerous is Ich and Its Secondary Infection?

You already know about ich and how dangerous it can be. But ich makes your fish susceptible to a secondary infection. Bacterial and fungal diseases can easily catch weaker fish.

Infected by more than one disease at a time is the worst thing for your fish (and for you, obviously!) In such cases, the chance of recovery is almost zero.

To prevent fish from a secondary attack, you have to watch your fish like a hawk during the medication. If things are seemed to worsen, stop the medicine and perform a complete water change.

Even after eliminating ich, the next weak is crucial for your fish, so keep watching them. All of these words sound like doom and gloom, but don’t lose hope. I wanna repeat, if you identify ich early, it is fully curable.

How to Prevent Ich

Prevention of ich infection is effortless. Just follow a few comfortably manageable tips, and I assure you ich will never attack your fish.

1) Get A Quarantine Tank

I am a big fan of quarantine tanks. Do you know why? They are a straightforward solution to many complex problems. Still, the surprising fact is, 95% of aquarists just ignore it! They don’t use a quarantine tank.

Anyway, keeping your new fish/plants/invertebrates isolated for a quarantine period is the best way to prevent ich from entering your aquarium. They shared common tanks in the pet store. So, it is very likely that they bring pathogens from there.

Isolating and medicating new aquarium members can relieve you from future hassles.

2) Keep A Healthy Water Condition

Keeping a tidy aquarium condition is hugely crucial. It is the solution to your 90% aquarium related problems. But how can you maintain a healthy aquarium? Follow the bullet points:

  • Have a three-stage filtration system. Perform filter media changes regularly.
  • Perform regular water changes and replace 10-20% of the aquarium water weekly.
  • Perform water tests routinely and take early action to any deviation in water parameters. 
  • Have live plants in the aquarium. Pick one or two plants initially that are suitable for beginners.

In a healthy tank, the nitrogen cycle is fully established. Keep running a nitrogen cycle is crucial to maintain the well-being of aquarium inhabitants.  

3) Never Overstock Your Aquarium

Overstocking is very harmful. It makes your fishkeeping more challenging. If you avoid overstocking, your job will be straightforward; believe me!

There is an interesting saying about fish stocking. Assume how much fish you can keep in your tank, and keep half of that!

An overstocked aquarium is very hard to manage once it is disease infected. Itch and other contagious diseases spread super faster in a jammed aquarium.


Prevention is always better than cure. Cleanliness is the key. Maintaining the water quality pristine, you can avoid not only ich but also any other infections.

Still, ich is not the death certificate for your fish, and it is fully curable. BUT, you have to diagnose the disease in the early stages. In a more advanced stage, it is tough to cure.

I hope this article will guide you in taking the right action to remedy your beloved pets, who are suffering from ich.

From more experienced aquarists, I would like to know how do you treat ich. Please share your experience in the comment box below.

Sujit Modak

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