Goldfish Lice: Causes, Symptoms, Prevention, & Treatment

Do you feel your Goldfish is lethargic? Do you feel your Goldfish is not eating its feed properly? Is your Goldfish behaving weirdly like bumping or rubbing itself with the walls of the aquarium or the decorations in the fish tank or aquarium? Is your Goldfish flashing? Are there any green or grey dots on your Goldfish?

Goldfish lice are actually a type of crustacean whose Latin name is Argulus trilineatus. They attach themselves to Goldfish bodies and feed on their blood. Goldfish lice are too infectious, they are carriers of many other diseases.

I love Goldfish since my childhood. I loved their radiant colors. Seeing my interest my parents gave me Goldfish as a gift. From that day till now, my love for Goldfish increased day by day. To look after your Goldfish properly it is very important to know how to handle them. In this article, I will share with you everything that I have learned from my own experiences with Goldfish Lice.

What are these Goldfish Lice?

Goldfish lice are microscopic parasites. Goldfish lice are a type of parasitic Crustacean, their scientific name is Argulus Trilineatus. When they are adults, they are approximately 3 to 4 mm long. They are mostly translucent with circular shells and eight legs. Just like mosquitoes, they suck blood. Goldfish lice have a hook-like structure from which it attaches themselves to the Goldfish body and sucks blood.

Goldfish Lice

Female lice are a little bigger than males.  Moreover, a heavy infestation of Lice is dangerous for Goldfish life. Female lice lay eggs that are covered with jelly-like substances. These lice eggs hatch quickly if the temperature of the water is high the process of hatching is slow in cold water. The newly hatched larvae survive for one to two days on their yolks but after that, they need a host. Therefore, they attach themselves to the Goldfish with their claws and suck its blood and grow. On the contrary, adult Lice can survive without a host for approximately 2 weeks.

What are the causes of Lice on your Goldfish?

First of all, I will tell you the causes of Goldfish Lice.

  1. The most common reason is putting new Goldfish in your aquarium without quarantine.
  2. Putting new ornaments or decorations in the aquarium or fish tank without washing or checking them.
  3. Buying Goldfish from an unclean shop or their aquarium or fish tank is dirty and infected.
  4. Without checking properly put green plants in an aquarium or fish tank.
  5. Not cleaning your aquarium or fish tank regularly.
  6. In ponds frogs, toads and turtles can also spread Goldfish Lice.

What are the symptoms of Lice on your Goldfish?

Lice can cause uncomfortable symptoms in your Goldfish. Some of the symptoms are as follows.

  1. Due to their size, adult lice can be seen with the naked eye.
  2. These Lice suck blood from Goldfish so the fish become lethargic.
  3. Goldfish become anemic so their color also changes.
  4. Goldfish behave abnormally, and weirdly, and stressful.
  5. Goldfish rub themselves against the walls, ornaments, and decorations of aquariums or fish tanks because of the itch caused by Lice.
  6. Grey, green, or brownish slightly raised spots are the sign of the presence of lice on Goldfish.
  7. Goldfish scales are broken and torn fins.

How to Prevent Goldfish Lice?

As you know Prevention is better than cure there are some ways and by following those ways, we can prevent Goldfish Lice pests to enter our aquarium or fish tank. Resulting in the complete safety of our precious Goldfish.

  1. Choose the best clean shop for buying Goldfish or other things for your aquarium like decorations, green or artificial plants, etc. so, so these things will not become the carrier of lice and will not infect your aquarium.
  2. Don’t overcrowd your aquarium or fish tank.
  3. You should quarantine new fish for 12 to 15 days before putting them in your aquarium. This quarantine will prevent infection to spread in your existing fish.
  4. If you are adding artificial plants or stones or decorations first sterilize them before putting them in your aquarium or fish tank.
  5. When you want to buy a Goldfish first check the aquarium or fish tank of that shop. If you feel that the aquarium or fish tank of the shop is dirty or contains any dead or sick fish don’t buy Goldfish from that shop.

If you are following all these basic things there is no chance that any lice will enter your aquarium or fish tank. Your Goldfish will be happy and healthy.

As some symptoms of Goldfish Lice are common and like other diseases. So, you must observe your Goldfish keenly. And, if you find any Lice on your precious Goldfish don’t feel sad or depressed because now you already know the causes and symptoms of Goldfish Lice. I know a lot about the treatment of Goldfish Lice because of my own experiences. Now I will share my experiences with you.

How to Treat Goldfish Lice?

Manual Treatment

Due to the size of Goldfish Lice, we can see them with our naked eye especially when they are an adult. So, pick your Goldfish in a damp cloth and check vigilantly the presence of lice and remove them carefully with the help of tweezers. Also, check your aquarium ornaments or decorations and green or artificial plants. Wash all the things. If possible, dip plants in diluted bleach or Hydrogen peroxide.  

manually treatment of goldfish lice

Look carefully don’t mix Lice with algae or dirt. For this manual treatment, you can do it yourself or you can take your fish to a certified vet. The result of the removal of Lice by this manual process is not 100 % because you can remove adult lice, but small larvae are not easy to spot or remove.

Appropriate Temperature

Managing the temperature of the water is very important. The warmer the water is, the faster the life cycle of pests, parasites, or Goldfish Lice. You must consult a vet before adjusting the temperature. Don’t increase the temperature suddenly. Increase the temperature slowly so that Goldfish will adjust itself to the temperature.

Salt Treatment

Put two teaspoons of salt in 1 gallon of water and dip your Goldfish in this water for a couple of days. It is a very easy and best home remedy.


Medicine that has cyromazine as an active ingredient is very effective for treating Goldfish Lice. Cyromazine is an antiparasitic it limits the parasites to reproduction and with its continuous usage, these Lice die. If you have treated your Goldfish with cyromazine and you still notice the presence of Goldfish Lice, you may need to repeat the treatment.


Another effective medicine is Diptera. It is very good for killing lice completely. It comes in liquid and powder form. Remember to follow the safety and dosage instructions strictly because overdose is toxic for Goldfish. There should be water circulation in the aquarium or water tank so that Dipterex will spread evenly in the water and due to this circulation, this medicine will reach all things in the aquarium from Goldfish to decorations and plants, etc.

Microbe-Lift Treatment

Another effective medicine that is safer and treats other infections or pests in your Goldfish and aquarium is Ecological Labs LAWP16 Microbe-Lift Lice treatment. Follow the instructions to give the proper dose of this medicine neither low dose nor high. A high dose is toxic for Goldfish. Carefully observe your Goldfish for any toxic or overdose reactions for example lethargy, looking breathless, or turning sideward.

Good Water Quality

Maintaining good water quality is very important. Change water frequently and the source from where water is coming must be clean.

Wash Frequently

It takes almost two months for Lice to complete their life cycle, so it is very important to wash the fish tank or aquarium using disinfectant thoroughly for several days. By this, we will get rid of lice eggs.

Check pH and Temperature

Make sure to regularly check the temperature and PH level of water.

Follow Up Treatment

Follow-up treatment is a must in treating Goldfish Lice. Dip Goldfish in non-iodized salt two teaspoons per gallon for a few days. By doing this you will also get rid of Goldfish lice and prevent bacterial and fungal growth.

Are Goldfish Lice Deadly?

Unfortunately, YES Goldfish lice spread very fast and if you will not observe your Goldfish properly or not clean or not maintain your Goldfish and its habitat then it is very dangerous for your Goldfish. If you will not treat them quickly, they are extremely dangerous.

Lice food is your Goldfish blood. So, too many lice can make your Goldfish anemic or lethargic. These lice mostly stay on Goldfish for two hours after that it drops off and start finding a new host. These lice not only suck blood but also make wounds or cuts on Goldfish skin. These wounds or cuts on the skin of Goldfish mean that Goldfish are more prone to bacterial infections. Another negative thing about these Goldfish lice is that they may harbor other parasites or diseases your Goldfish. So, early identification and treatment will keep your Goldfish safe.

The Bottom Line on Goldfish Lice

Pets are very important to us whether dogs, cats, birds, or fish. Goldfish are pretty, cute, and very innocent pets. We should take care of them properly.  Your behavior must be consistent. Maintain the quality, cleanliness, and habitat of goldfish. A healthy lifestyle is important for humans and it is equally important for animals. Give your Goldfish the best quality diet. It is best to discuss which feed to give with your vet. Clean your aquarium or fish tank regularly. If you find any lice on your Goldfish or any other disease symptoms quickly start treatment. However, starting from natural remedies. Because they are free from side effects. I will recommend natural remedies because they are not intense for your Goldfish and its habitat. However, if you feel that medication is necessary go for it never takes any risk to the health of your Goldfish. Now you know almost everything about Goldfish Lice, best of luck.

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