Betta Illness Photo & Symptoms Guide

About This Guide

In this guide we provide information and photos to help you identify betta illnesses. We cover the key symptoms, and use photos to help explain the descriptions. If your betta is sick, we hope it makes a swift recovery and we’ll do our best to help.

Please be aware that this guide is not intended to be the complete guide to betta illness, but rather an assistive tool, and we provide more detailed information, including suggestions for medicine and usage of salt, in the betta illness section on our website.

By no means should this guide be used as the sole source of reference when curing your betta. It should be used as a guide towards making the right moves when it comes to ridding your fish’s aliment. It’s always best to do a substantial amount of research before deciding on medication for your betta.

Some Betta illness can be a tiresome and complex issue - how the curing process takes place will of course depend on the illness in the first place. Obviously one cure does not fit all. For example, curing a fungal infection does not take the same method as curing Velvet. Sometimes, using the wrong medication for an illness can be more worse than good!

Remember, prevention is better than cure, so the more you learn about illness before it occurs, the better prepared you will be should it happen. There’s an adage in the fish keeping world that goes:

“Fish keepers do not keep fish, they keep water”. This is because poor water conditions are responsible for the vast majority of illnesses. Keep your water at a high standard and you’ve already won half the battle of illness prevention.

Fin Rot

Fin rot is caused by bacteria eating away at your fish’s fins. Any healthy aquarium has bacteria in it -- it’s what’sneeded to break down waste. Betta fish develop fin rot when kept in water that’s not clean enough.

About Fin Rot

Bacteria that thrives in dirty water can then infect the weakened betta. Fin rot is not caused by one specific typeof harmful bacteria, more so an overwhelming of aquarium bacteria. However, if your betta is injured for whatever reason - maybe it’s ripped its tale on an aquarium decoration, for example - this will make the fish more susceptible to fin rot/a bacterial infection. The chances of a minor rip or wound advancing into fin rot is minor if your fish is well maintained and looked after.Only if the fish becomes stressed (which can occur due to poor keeping and/or poor aquarium conditions) its immune system will weaken thus making it more susceptible. Read more about fin rot here on our website.

The fins may look short and decayed with split and ragged edges. Holes may also appear in the fins.


  • Frayed or ragged edges
  • Fins falling apart
  • Small holes appearing in the fins
  • The edge of the fins turning red, black or white
  • The base of the fins appearing inflamed or slimy
  • The fins seeming thin, colourless or transparent


In its simplest form, velvet is a parasite. The main way a betta can become exposed to the parasite is when a fish with the infection is added to the aquarium.

About Velvet

Velvet can be one (or more) of several parasites known aspiscinoodinium. The main way a betta can become exposed to the parasite is when a fish with the infection is added to the aquarium. Velvet is very contagious so it can spread quickly to other fish. It can also hitchhike on things like plants, previously used aquarium décor or other aquarium inhabitants like shrimp or snails. Read more about velvet here on our website.

Velvet manifests closely together, often clumping on the fish’s skin. It can be seen as a fine yellow dust.
This detailed image clearly shows a mass covering of velvet on a bettas face.
A flash light can be shined onto a betta to clearly show head and body covered with Velvet


  • The main sign of Velvet is a yellow or gold-like dust covering a betta, which will be easier to see if you shine a light onto the fish.
  • If your betta is suffering from Velvet, it may start rubbing itself against items in the aquarium.
  • General reactions to illness will also occur, such as a loss of colour, loss of appetite, lethargy and clamped fins.


Most of the time, popeye is simply a bacterial infection of the eye. A betta is not at all likely to contract it if it’skept in a clean aquarium.

About Popeye

A very dirty aquarium causes Popeye, in most cases. Popeye isn’t difficult to cure, but it can sometimes be an indication that your betta has a serious internal condition.

If that’s the case, then Popeye may prove fatal for your betta. Popeye is incurable if it’s a sign of a serious internal disease. Popeye can be a symptom of betta tuberculosis. Read more about popeye here on our website.

The eye will swell and extrude prominently from the body. If infected, a thick white growth may occur around and in the eye.
A betta with severe pop-eye. The infection has turned the infection completely white.
An above view of a betta with a bacterial infection in both eyes, causing popeye.


  • The main sign of Popeye is a bulging, swollen eye.
  • The eye may also have a thick white ring around it.
  • General reactions to illness will also occur, such as a loss of appetite and lethargy.


Ick, also known as ‘Ich’ or ‘White Spot’, is an external parasite that latches onto the body of a betta, causingirritation, itchiness and malaise

About White Spot

The parasite stays on the fish for up to 4 or 5 days before it drops off, reproduces, and then latches back onto the fish.
Ick is fairly easy to treat - especially if you catch it early on - but if left untreated, it can swarm the fish and lead to fatality.

Read more about ick here on our website.

Compared to velvet, ick is a lot more sparse on the fish. The growths are also white and slightly larger.
The dark, black face of this betta clearly shows the white spots ick causes.
The main growth of ick on this betta shows on the fins and face.


  • The main sign of Ick is white spots covering the body of the betta, making the betta look like it’s covered in a white dust.
  • The betta may start rubbing itself against objects in the aquarium (this is typical of Ick).
  • General reactions to illness will also occur, such as a loss of appetite, lethargy and clamped fins.

Fungal Infection

A fungal infection is when a fungus grows and eats the skin, fins and mouth of a fish (in this case, a betta). Itappears as a white, cotton-like slime on the fish.

About Fungal Infections

Fortunately, most fungal infections only attack the external tissues of fish. Most infections are usually caused by a pre-existing infection or injury. Fungi are present throughout most aquariums, but certain conditions increase the possibility of fungal infections, such as poor water quality, or a stressed or injured fish.

Read more about fungal infections here on our website.

Thick white cotton-like growths are a clear sign of fungal infection. Sometimes the infection can occur when a fish has been wounded.
A long cotton-like fungal infection growing on a wound on a betta face.
A long cotton-like fungal infection growing on a wound on a betta face.


  • The main sign of Ick is white spots covering the body of the betta, making the betta look like it’s covered in a white dust.
  • The betta may start rubbing itself against objects in the aquarium (this is typical of Ick).
  • General reactions to illness will also occur, such as a loss of appetite, lethargy and clamped fins.

Bacterial Infection

A bacterial infection can occur if there’s an overwhelming amount of bacteria in the fish’s aquarium or if the fishis in a high state of vulnerability (that is, if it has a very low immune system)

About Bacterial Infections

Even if an aquarium appears spotless, there’s still bacteria present in it, and if the fish is unwell, certain bacteria will start to infect the fish. It can be hard to know what’s caused a bacterial infection and how it’s affecting the fish. The betta on the right appears to have translucent skin and decaying scales. This could be a subcutaneous infection or an affect of an internal infection. Dropsy is also a huge indicator of an internal bacterial infection; the fish will swell and his or her scales will pine cone.

Read more about bacterial infections here on our website.

An external infection may cause the fish’s skin to become colorless, disfigured or transparent. If internal, the fish may bloat, deform or dropsy may occur.


  • One of the noticeable signs of an internal bacterial infection is lethargy.
  • Swim bladder disorder and dropsy can also occur. The betta may sit around a lot and flop to one side when perched on a leaf.
  • It may also have difficulty swimming or may not eat as much.
  • General reactions to the illness will also occur, such as a loss of colour and clamped fins.
  • You may notice a cloudy slime falling from the fish, or the betta may be covered in a slimy white layer if it is having problems with its slime coat. If the skin has a bacterial infection, white patches or blotchy sores can appear on the fish’s body.


There isn’t much evidence to explain what causes betta dropsy; it’s all very vague in the world of betta keeping.Dropsy is the process of fluid building up inside a betta (usually swelling of the kidneys).

About Dropsy

This disease is associated with organ failure. It’s believed to be caused by poor water quality and diseases contracted from live food. Dropsy isn’t contagious but the bacteria, which is believed to be a cause of it, is.

Read more about dropsey here on our website.

The fish will become extremely bloated or sometimes disfigured. The scales will raise causing what’s known as a ‘pinecone’ effect.


  • When the fluid builds inside the betta’s body, it causes the betta's scales to rise, giving the flesh a pine cone appearance.
  • The main sign of dropsy is raised scales (this is easier to identify if you look at your fish from the top), an extended / bloated stomach, lethargy and resilience to feeding.


Swim bladder disorder is when a betta has a disrupted swim bladder. This can be caused by overfeeding or it can occur with younger bettas when their swim bladders are not yet fully formed.

About Swim Bladder Disorder

This disorder is commonly seen in betta keeping and it usually just goes away by itself. It’s not contagious.Sometimes it can be a symptom of a bacterial infection ora fin injury. If the fins seem fine but the fish seems lethargic, has clamped fins or discolouration, try our cure for bacterial infection.

Read more about swim bladder disorder here on our

The fish will be lethargic, tired from attempting to swim with SBD. The fish may surface or rest on its side. A bloated stomach may mean the fish has been overfed.
Betta surfaced sideways, having difficulty trying to swim due to swim bladder disorder.
This betta is shown to have a fungal infection and fin rot, SBD has occurred due to these illnesses.


It's likely that a keeper will encounter it at some point, so it’s useful to be aware of its symptoms as soon as you own a betta:
  • If your betta does have Swim Bladder Disorder, it may appear lethargic or look like it has difficulty swimming.
  • It may wiggle on the aquarium floor or it may not move at all


Before we get started we should mention that it’s quite rare for a betta to contract tuberculosis, so don’t panic if your betta starts exhibiting one of the symptoms that can be indicative of TB.

About Bacterial Infections

The chances are it’s a different illness altogether and with the right treatment your betta will make a recovery. Ultimately, the bacteria will attack the internal organs (especially liver and kidneys), causing organ failure. This is when the symptoms of TB will show - such as raised scales, bloated body - and will be swiftly followed by death. This is the only fish disease known to be contagious to man, although the good news is it’s very hard to contract tuberculosis from a fish. Fish tuberculosis can be resident in water but has also been linked to live foods (researchers found cases of live foods infected by tuberculosis), and is mainly passed by ingestion (eating contaminated live food, or eating a dead fish that was a carrier, etc...).

Read more about tuberculosis here on our website.

The fish will become extremely bloated and will appear to decay rapidly. Lethargy, misbalance, loss of color and clamped fins are a few of the main symptoms of TB.
Betta fins become limp. The betta is extremely bloated and degrades rapidly. Dropsy will occur, the fish bloats and the scales pinecone


Betta Tuberculosis is a slow-blooming disease that a betta can have for up to 6 months before exhibiting any symptoms. If your betta is suffering from tuberculosis, its health suddenly start to deteriorate. He or she may start losing weight, grow body deformities such as popeye, suffer from bloated gills and scales, red clamped gills, raised scales (otherwise known as pine-coning), fin and body rot, red patches on its body and grey lesions along its side. The symptoms can really vary with tuberculosis -- a betta can get some of them, none of them or all of them, but will die very soon after contraction if it is indeed tuberculosis that it’s suffering from. However, just because a betta has any of the symptoms shown above, it doesn’t necessarily mean it has tuberculosis.

Table of Symptoms

Illness & Rarity

Possible Symptoms

Fin Rot

Very Common

Decayed fins, slimy fins, tethering fins. Abnormal lethargy. Fins will look shorter than normal, loss of colour. Areas of finnage may appear red. Clamped fins



A fine yellow dust-like covering on the fish, the fish may seem inactive, abnormally lethargic, may be more hesitant to eat, a loss of color. Typical to velvet: the fish may rub him/herself against surfaces in the aquarium such as gravel, plants, and decorations.


Rarely Occurs

Typical of popeye: the bettas eye/eyes may be abnormally bulged and may become clouded. The betta will become lethargic, may have a loss of colour and may be more hesitant to feed.



The fish will have a clear covering of white speckles, looking like salt grains. The fish may seem inactive, abnormally lethargic, may be more hesitant to eat, may suffer a loss of color. Typical to ick: the fish may rub him/herself against surfaces in the aquarium such as gravel, plants and decorations.

Fungal Infection


The betta will have white cotton-like growths on his or her head/body. Depending on the severity of the infection the betta may become lethargic, colourless, reclusive, have clamped fins and a loss of appetite.

Internal Infection

Very Rare

The fish will become heavily bloated causing the body to bow outwards, this will cause the scales to rise and protrude, resembling a pinecone. A range of other symptoms will follow like lethargy, a lack of attempt to feed, discolouration, clamped fins and often swimming disorder/swim bladder disorder. 9/10 times, sadly, dropsy leads to fatality.



Swim Bladder Disorder (SBD) can sometimes be a birth defect; some betta fry are born with SBD and grow out of it or it can cause them to live a shorter life span if they do not. It can also be considered a symptom of other diseases, much like a running nose is to a cold. If your fish has SBD it will be swimming uncontrollably and most likely be very lethargic because of this, which may also cause it to feed and surface for air less frequently. The fish may become stressed and colourless with clamped fins. If an adult betta is afflicted with SBD, it may be a symptom to a serious internal illness but can also be indicative of something less severe like constipation. Bettas will often contract SBD when overfed and become constipated.


Very Rare

Tuberculosis is an extremely rare disease for a betta to contract. It is incurable; by the time the symptoms emerge your fish will not have long to live. The main symptom of TB is the instant deterioration of your fish. It will go from seeming perfectly healthy to having contracted dropsy, SBD, lethargy, loss of colour, clamped fins and sometimes popeye will also occur. Your fish will contract dropsy if infected with TB. Sadly, dropsy almost always leads to fatality.