Illness and Disease Fish Tank Guides

Epistylis – Fish illness


Epistylis is a common illness for ornamental fish. It is often confused with White spot/Ich as the two appear similar to the naked eye. Epistylis gives Ich a bad name as it is more fatal, so it is important to be able to tell the difference between the two.

Epistylis – Fish illness

Epistylis is a disease commonly found in aquarium fish. In many cases, it can easily be confused with White spot/Ich, or as a fungus, due to the visual effect it creates on the fish.

Epistylis is just as common in the aquarium as White spot and it most commonly occurs in new aquariums. But Epistylis is more deadly than White spot is.

Epistylis can be seen on the fish as small white ‘tufts’, often on the fins at first but it can quickly spread all over the body, it can even attach to the fish’ eyes.

These immobile organisms attach themselves to the fish and can cause the fins and scales to erode. In large enough quantities, Epistylis is fatal but lucky for us it is treatable and even more easily preventable.

Note: There is currently a belief that epistylis is a new illness to enter our beloved aquariums, but it isn’t.

In the past, Ich has taken the credit for deaths caused by epistylis and Ich has unduly become a very feared parasite.

Ich is not very deadly, but when epistylis is mistaken for Ich and the old classic ‘turn up the heat’ advice is followed it can wipe a tank out quickly.

There is a lot of anecdotal evidence that increased heat accelerates the infection. Heat does not kill Ich either, so it is all round bad advice to increase the temperature in my opinion.

Diagnosing Epistylis

Epistylis appears as small white tufts on the fish, as these organisms are immobile, they usually first attach at places where the fish most comes into contact with other surfaces, such as the pectoral fins of catfish.

I’ve seen a lot of photos on social media where people immediately diagnose white spots on a fish as white spot disease.

This is totally understandable as the two often look very similar.

On appearance, these organisms may also look like a fungus and, because of this, Epistylis is often referred to as a false fungal infection.

It is actually quite difficult to distinguish by the naked eye between White spot, Epistylis and fungal infection.

The best ways to tell the difference are:

  • White spot/Ich usually appears as white dots no larger than a grain of salt. Epistylis will grow up slightly into the water column from the fish.
  • Epistylis is often clustered. White spot tends to be spread fairly evenly across the body.
  • Epistylis regularly affects the eyes of the fish. White spot rarely does.
  • Epistylis often appears to be very white, Fungal/bacterial infections tend to be more grey in colour and sometimes brown/gold.
  • Columnaris usually starts as a single larger patch. Epistylis appears in many small patches.


Epistylis 2

(Photo Credit –

Treating Epistylis

Treating Epistylis is vital, as I mentioned, it is far more deadly than the dreaded White spot, infact, White spot probably gets a worse reputation than it deserves due to Epistylis being confused for it.

So how do we treat it?

Epistylis doesn’t feed on the fish itself, it feeds on bacteria, but it often causes bacteria and infection to attack the fish where it has damaged the scales/fins.

It’s a good idea to treat fish with medicated anti-biotic food, this will help to prevent any other infections, such as fin rot, from affecting the fish.

Anti-bacterial medications are a good idea too, as they will remove the food that the Epistylis feeds on and will help to protect the fish further from secondary infection.

To treat Epistylis, Salt baths have been shown to have a really positive effect.

It is recommended that a salt bath of 5 level teaspoons for each litre of water is given to the affected fish daily for up to 10 minutes at a time, or until the fish loses buoyancy and rolls over.

You will also need to take the preventative measures listed below:


Preventing Epistylis

Preventing Epistylis is fairly easy, the organism feeds on bacteria, so keeping a clean, healthy aquarium is the key to preventing it.

A good maintenance routine is essential to keep your aquarium clean, but there are a few things to consider:


Filtration needs to be capable of keeping the aquarium clean, so your filter needs to be powerful enough, full of beneficial bacteria and well maintained.

If you have a new aquarium and a new filter, there is a good chance that there are no bacteria in the filter to keep your aquarium clean.

If that is the case, it is a good idea to get hold of some mature filter media as this will enable you to establish a colony of useful bacteria in your filter much quicker.

This will help your aquarium to cycle quicker too, which will help you to avoid other issues.


Aerated water is essential in the aquarium. Despite living under-water, fish need oxygen. The best way to introduce oxygen to the aquarium is to create surface agitation. There are several ways to do this.

Air pumps will create some surface agitation and certainly have their uses in the aquarium.

Alternatively, you can angle your filter outlet towards the surface of the water.

Or, you could use a wavemaker to agitate the surface and increase circulation.


Circulation is important for a clean, healthy aquarium.

Without enough circulation, you may find that you have areas where dirt and debris can accumulate. This can become a breeding ground for the kind of bacteria you do not want in your aquarium.

So if your filter isn’t strong enough to fully circulate water around your aquarium, or you get dead spots, a wavemaker or powerhead is a great idea.



This is fairly common in the aquarium, particularly in new setups. So it’s worth looking out for.

It is often confused with White spot/Ich and whilst some reports suggest that White spot medication can be effective many also report that it isn’t.

So, if you have been treating for White spot, but it isn’t getting better and fish are dying left right and centre, then it may be time to consider that it may be Epistylis.


Check out our list of recommended medications in our ‘Shop’: HERE


Frequently Asked Questions

What is Epistylis

Epistylis is a disease commonly found in aquarium fish. In many cases, it can easily be confused with White spot/Ich, or as a fungus, due to the visual effect it creates on the fish.

How to Diagnose Epistylis

Epistylis appears as small white tufts on the fish, as these organisms are immobile, they usually first attach at places where the fish most comes into contact with other surfaces, such as the pectoral fins of catfish.

What is the difference between Epistylis and Ich?

Ich/White spot appears like grains of salt stuck to the fish. Epistylis appears to be more 'fluffy' and grows upwards, away from the fish' body. Epistylis is more deadly than Ich and requires strong salt baths as treatment.


About the author

James @Seriously Fishy

I am a fish keeping enthusiast with over 20 years experience. I currently keep American Cichlids (CA) which are my favourite fish to keep so far. I started Seriously Fishy as I noticed a large volume of people on various web pages looking for help with Aquarium basics. I created the first Seriously Fishy book to solve the issue in 28 pages, that led to the Seriously Fishy UK fish forum and blog.

Leave a Comment


  • Hi James,
    Thank you for this article about EPISTYLIS fish illness. I have a Betta that is very sick and it seems that is Epistylis.
    I started with the salt bath (3rd bath today) but he seems to be very weak and the golden looked like strings on his fins doesn’t look any better.
    I’m desperately looking for a treatment.
    What do you recommend, which antibiotic should I buy to solve the problem?
    Please let me know asap to save JAWZY my grandson’s fish.
    Thank you for your help!
    Blessings, Dora

    • Hi Dora. There is an antibiotic called Marycin (hopefully I’ve spelled that correctly) that is ideal for adding to fish food to treat epistylis. Keep the salt baths up and I’ll cross my fingers that your Betta makes a full recovery! 🤞

  • Please help! My BP cichlid has been sick for about a week. He was laying at the bottom of his tank for a day or two, then we saw white dots and began treatment for ick. 50% water change, raised temp, salt bath for 15 min, on 3rd day of Paraguard. He swam up to the top of his tank after first treatment but stays in on spot, not swimming really but leans on wall over bubble stone. Occasionally flashes then returns to his same spot. Not eating at all. Yesterday just spots but today looks different- more like epistylis photos.
    Tank is 55 gal, only Jimmy and 3 tiger otos to help keep it clean. Water parameters are good, 0 nitrates, 0 nitrites, ph 7.4, current temp at 84 (usually about 79, have been warming it up per ick treatment instructions). This morning water had copper at 1ppm, I do have some Cuprasorb but not sure about multiple treatments at once?

    • Just to add – tank and cichlid are 2 yrs old. Ottos were added about 2 weeks ago. No live plants because Jimmy tears them up, rock and sand substrate.

    • Hi Emily! I’ve seen below that your tank has been running for two years and isn’t planted, if that’s the case there should be some nitrate in the water so it may be worth checking your test kit Is in date and testing for ammonia too.

      With regards to the spots, it’d be hard to say which they are without some more description or a photo. Tag us in a photo of the fish on Instagram and I’ll have a look.

      Raising the temp isn’t always the best idea. It doesn’t really help for Ich and, as mentioned in this article, there is anecdotal evidence that it can make epistylis much worse.