Fish Internal Parasite Treatment – Best Fish Keeping

Last updated on December 24th, 2022 at 11:04 am

Parasitic Infections Of Fish

All major groups of animal parasites are found in fish, and it appears that healthy wild fish usually carry a large number of parasites. Parasites with direct life cycles can be important pathogens in farmed fish. Parasites with an indirect life cycle often use fish as intermediate hosts. Knowledge of specific host fish greatly facilitates the identification of parasites with marked host and tissue specificity, while others are recognized due to their frequent occurrence and lack of host specificity. Examination of fresh smears containing live parasites is usually diagnostic.

Ich ( Ick’s disease or white spot)        

Ich is one of the most frequent and persistent parasitic diseases in aquariums. It occurs when a protozon attacks and attaches itself to the body, fins, and gills of fish.             

Physical characters

  • White spots on the body and gills.
  • The white spots can combine to form white spots.
  • Tight fins

Behavioral signs

  • Difficulty breathing. Your fish may pant on the surface or stay on the filter to get more oxygen.   
  • Loss of appetite
  • Your fish can rub against objects in the aquarium.      

Possible causes

One of the main causes of this disease is a sudden drop in temperature . This can be done during the colder winter months or when the replacement water temperature is lower.              

Outbreaks can also occur if you incubate the disease in a poorly maintained aquarium. As well as decorations or plants that carry the parasite’s cysts.   

Possible treatments

Once parasites have settled in your aquarium, they are difficult to control due to the speed at which they multiply. If you don’t control it, there is a 100% death rate . Therefore , it is important to act quickly .                    

Because the disease is so common, you can easily buy medication at your local water store or online. Follow the directions carefully and always remove the charcoal from your filter when taking any medication.   

You must use other treatments in addition to medication. Increase the water temperature up to 30 ° C (if your fish can handle it) as this will speed up the life cycle of the parasite.           

Combining aquarium salt ( not table salt) with high temperatures will continue to kill me effectively. Salt can disrupt the ego’s fluid regulation and help fish’s natural mucous membranes protect them from the parasite.           

Velvet (gold dust disease)

Also known as “rust,” it is a common disease in aquarium fish and has the potential to kill anyone in your aquarium.

Caused by a species called oodynium , it is found and attaches to the skin and gills of fish. Destruction of cells and supply of the nutrients they contain.            

When the feeding ends, it falls off and divides into dozens of cells.

Physical characters

  • A thin yellow or light brown film on the skin.
  • In advanced stages, the skin peels off.
  • Tight fins

Behavioral signs

  • Scratch hard objects
  • Lethargic behavior
  • Fast and labored breathing
  • Loss of appetite and weight loss.

Possible causes

Velvet disease is caused by one of the many types of oodynium and is common in poorly maintained aquariums.         

Including abrupt changes in water temperature, infrequent water changes, adding new fish without quarantine, and introducing cyst plants (new plants must be disinfected prior to introduction)

Possible treatments

It is very contagious and is usually in an advanced stage before it is diagnosed. Therefore, you must act as quickly as possible.  

Common drugs are copper sulfate, methylene blue, formalin, malachite green, and acriflavin .          

All of this is found in the fish medicines used to fight this disease. Always remember to remove activated charcoal when handling your tank.   

Samtparasiten depends for part of its energy on photosynthesis. Therefore, dimming your aquarium lights or leaving your aquarium in complete darkness can make the treatment process easier.              

Increasing the water temperature can speed up the process. But if this tactic is not feasible for all fish and can also induce stress, it further weakens the immune system of the fish.      

Hole of the head ( erosion head and sideline)

Hole in the Head Disease in Fish, Causes, Symptoms, Treatment


This parasitic disease, also known as hexamitosis , can affect both freshwater and saltwater fish. Lesions can appear on the head and sides of the fish, hence the name: Hole in the head.             

This infection can also be responsible for Head and Lateral Erosion Disease (HILLE) in fish.

Physical characters

  • Pale eroded holes on the head.
  • Fish may appear to be eaten alive
  • The coloring is off

Behavioral signs

  • It does not occur often until the disease is severe
  • May show general signs of lethargy.
  • You may have difficulty swimming due to loss of balance.

Pro Tip: Not all kinds of fish appear the same symptoms, and not always in the same grade lesions develop.    

Possible causes

The causes of this disease have been debated for a long time and no one can say for sure what the main trigger is.

However, the most commonly accepted cause is the use of activated charcoal in closed aquarium ecosystems.        

Other factors can include nutritional deficiencies, especially important vitamins and iodine in the diet.

The quality of the water can also play a role. Aquariums rich in nitrates can lead to the development of diseases in fish.   

Possible treatments

If the infected fish have developed pale, eroded holes on their heads, they are in real trouble.

Open lesions provide an entry point for other pathogens that can cause other diseases.

But it is possible to improve infected fish by removing all of the activated carbon and doing a large percentage of water changes .                    

Diet improvements have also been shown to be beneficial for fish.

Neon tetra disease

Neon Tetra Disease (Plistophora hyphessobryconis) |

It can infect a wide variety of tetra species. It is a series of bacterial infections caused by a parasite that invades the fish, enters the stomach and digestive tract and eats the fish upside down.   

Physical characters

  • Cysts in the body
  • Loss of color in the red and / or milky / brownish band
  • Playful pale areas around the back.
  • Weightloss
  • In extreme cases, the fish’s spine can curl.
  • The advanced stages can lead to secondary bacterial infections that cause gas and popeye

Behavioral signs

  • Difficulty swimming
  • Irregular swimming
  • School separation

Possible causes

Caused by a parasitic organism called Pleistophora Hyphessobryconis , it feeds on fish until they die.          

This can happen when fish eat other dead fish or even eat live food. Live food can act as a support and transfer it to your fish as soon as they consume it.   

Possible treatments

Unfortunately, there are currently no medications or treatments available for infected fish. You must dispose of infected fish and slaughter them humanely to avoid further contamination.           

Your best course of action would be to take safety measures against a second outbreak. You can do this by keeping the water level high and cleaning it regularly.   

When buying new fish, be very strict with your selection and always quarantine them for a few weeks before introducing them.

Fungal infections of fish

Fungal Disease In Betta Fish

Body fungus

Fungi are opportunistic and, when given the opportunity, invade most organic matter, including living tissues.

If you keep your aquarium fish healthy, you shouldn’t have a problem because the mucus layer on your skin prevents spores from infecting living tissues.

Physical characters

  • Long, white, fluffy strands emerge from the body (they can also grow on the head and fins)
  • Dirt can turn them brown, reddish, or green.

Behavioral signs

  • It is usually affected in later stages

Possible causes

Body fungi often occur when the slimy coating of fish is damaged and they live in unsanitary conditions. Rough handling, tightening of the fins, and fighting can damage the mucus.   

Diseases that cause open sores like ego, ulcers, and hole-in-the-head disease can also lead to body fungus.

Environmental stress caused by cooling, poor water quality, and poor water chemistry can weaken the immune system of fish and lead to fungal growth.        

Possible treatments

You must act quickly because it can spread quickly to your fish, making them prone to secondary infections. And the fungus itself will kill the fish if left untreated.   

There are a number of commercial drugs that are used to treat body fungi. They are usually based on organic dyes such as malachite green.   

However, antifungal medications are not suitable for all types. So isolate the fish in a hospital tank.  

Cotton fin fungus

Struggling With Cotton Fin Fungus? Here's The Cure

Also known as cottonseed disease, this is a disease that generally affects aquarium fish with weakened immune systems.

Marked by cotton growth, it is quite common and it is important to repair it immediately before it can cause much damage.

Cotton fin is similar to cottonmouth disease, but cottonmouth is a serious bacterial infection called a mouth fungus (although it is not a fungus).

It can be difficult to distinguish the two, but in general Cotton Mouth has a rougher, grainy appearance and can be a dull whitish color than a true white mushroom.

Physical characters

  • Cotton-like, fluffy or fluffy growth on the fins

Behavioral signs

  • There are no signs of actual behavior. Fish tend to do well until the fungus appears on the surface of the skin.   

Possible causes

Poor quality water, corrosive materials, and poor tank maintenance can produce cotton fins.

Even if you are very good at maintaining your aquarium, old or injured fish can become infected with the disease. Especially if your fish is bullied or fights a lot.   

Possible treatments

You will be pleased to know that treatment is relatively simple and can be done with the treatment fungal .               

The four bases used are salt, methylene blue, malachite green, and acriflavin (although it is now removed because it can be toxic to humans).

Malachite green is readily available and known to be effective. You can also add aquarium salt to your tank at the rate of 1 to 3 grams per liter .              

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