90 Gallon Tank Strange Parasites on My Fish - Help!

[alejandrorod]

My fish had two transparent, stick-like parasites protruding from its side. After doing some research, I found that they resembled anchor worms, but I need confirmation. I read that they can be removed with tweezers, so I carefully pulled them out. The larger one was approximately 1 cm long.

I need help identifying the parasite (if it’s not anchor worms) and understanding how to completely eliminate it, including any possible offspring it may have left behind.

The fish seems fine and remains very active. However, the spots where the “parasites” were removed are slightly red.

It is the only fish in the tank.

If you need any additional information or photos just ask.

My water parameters are perfect.

Any advice would be greatly appreciated!

 

[A201]

Fish dewormers such as Levamisole, or Prazipro
might be the answer.

 

[alejandrorod]

Fish dewormers such as Levamisole, or Prazipro
might be the answer.

Could API General Cure work? I have limited options when it comes to medication in my country. They are not regulated but my lfs don't carry them, they only have the most basics ones.

If I don't find any and have to order online for how long can my fish tank go untreated?

 

[A201]

You might give general cure a try. It is a combination of Metronidazole and Praziquantel.

 

[Fishfur]

Anchor worms are parasitic copepods and pulling them out isn’t necessarily the best idea - though what’s done is done.

The anchors often tear off and remain embedded, where they can cause serious infection in the wound. I would be soaking the wound in Methylene blue in hopes of staving off an infection.

Based on what I can see in the picture, the anchor is still inside one of the wounds, because it isn’t present on the shorter segment, only on the longer one (on the right side).

Additionally, the females start releasing eggs within a day of anchoring in a fish. Eggs hatch within a day or two.

So your tank is infected with nauplii (larvae) that will take around 4 days to go through 3 larval stages. Then they spend roughly the next 7 days moulting into various copepodid stages.

Males find females & mate & the females look for host fish. The male dies but the females anchored in a fish start laying eggs very quickly.

At a temperature of 29C, their entire life cycle is somewhere between 18-25 days long. It will be longer at lower temperatures.

There are a few options for treatment.

Potassium permanganate at a dose of 25 mg/L in a bath for at least a half an hour kills the larvae but may not kill adults that are not yet attached to fish.

Dimilin is a pesticide & chitin synthesis inhibitor. It’s a brand name for diflubenzuron. It will kill off moulting adults & larvae at a dose of 0.066 mg/litre.

If you can move the fish to a QT for 7 days that should be enough to break the life cycle of the Lernaeids in the main tank. Close observation afterward once fish have been returned to their main tank is a very good idea just in case.

Or you could move the fish out temporarily & just use salt to kill the parasites.

The minimum possible dose of salt, 4.8 grams per litre, would take at least 30 days to do the job but it’s unfortunately too high a salinity level for goldfish to tolerate for 30 days.

Without the fish being present, there is no need to worry about salinity tolerance so I’d use a very hefty dose of salt - equal to full strength seawater - 35 grams of salt per litre of water. It’s more than enough to stop eggs from hatching and kill larvae & adults.

Give the salt a day or two just to be sure & then drain & flush out the tank to remove the salt & refill. You’ll probably have to cycle again after this.

Could API General Cure work? I have limited options when it comes to medication in my country. They are not regulated but my lfs don't carry them, they only have the most basics ones.

If I don't find any and have to order online for how long can my fish tank go untreated?

General Cure will have zero effect on this parasite which is not a worm of any sort, but a crustacean, a parasitic copepod.

You might give general cure a try. It is a combination of Metronidazole and Praziquantel.

Just fyi, neither of those drugs, either singly or as a combo will be of any use. They won’t kill crustaceans like the Lernaeid copepods that we call anchor worms.

Fish dewormers such as Levamisole, or Prazipro
might be the answer.

Unfortunately, neither of those has any useful effect on anchor worm because they are not worms.

 

[alejandrorod]

Anchor worms are parasitic copepods and pulling them out isn’t necessarily the best idea - though what’s done is done.

The anchors often tear off and remain embedded, where they can cause serious infection in the wound. I would be soaking the wound in Methylene blue in hopes of staving off an infection.

Based on what I can see in the picture, the anchor is still inside one of the wounds, because it isn’t present on the shorter segment, only on the longer one (on the right side).

Additionally, the females start releasing eggs within a day of anchoring in a fish. Eggs hatch within a day or two.

So your tank is infected with nauplii (larvae) that will take around 4 days to go through 3 larval stages. Then they spend roughly the next 7 days moulting into various copepodid stages.

Males find females & mate & the females look for host fish. The male dies but the females anchored in a fish start laying eggs very quickly.

At a temperature of 29C, their entire life cycle is somewhere between 18-25 days long. It will be longer at lower temperatures.

There are a few options for treatment.

Potassium permanganate at a dose of 25 mg/L for at least a half an hour kills the larvae but may not kill adults that are not yet attached to fish.

Dimilin is a pesticide & growth regulator. It’s a brand name for diflubenzuron. It kills moulting adults & larvae at a dose of 0.066 mg/litre.

If you can move the fish to a QT for 7 days, that should be enough to break the life cycle. Close observation afterward once fish have been returned to their main tank is a very good idea just in case.

Or you could move the fish out temporarily & use salt to kill the parasites.

The minimum possible dose of salt, 4.8 grams per litre, would take at least 30 days to do the job and it’s unfortunately too high a salinity level for goldfish to tolerate for 30 days.

Without the fish being present, there is no need to worry about salinity tolerance so I’d use a very hefty dose of salt - at least equal to full strength seawater - 35 grams of salt per litre of water. It’s more than enough to stop eggs from hatching and kill larvae & adults.

Give the salt a day or two just to be sure & then drain & flush out the tank to remove the salt & refill. You’ll probably have to cycle again after this.


General Cure will have zero effect on this parasite which is not a worm of any sort, but a crustacean, a parasitic copepod.


Just fyi, neither of those drugs, either singly or as a combo will be of any use. They won’t kill crustaceans like the Lernaea copepods that we call anchor worms.


Unfortunately, neither of those has any useful effect on anchor worm because they are not worms.

Sorry if I got something wrong—it was a lot to take in, and English isn’t my first language.

From what I understood, I could remove the fish from the tank for at least seven days and monitor it in a quarantine tank without needing to add any medication, except for one to treat potential infections caused by the wounds.

After seven days, I can return my fish to the main tank since the adult parasites will have died due to not finding a host.

Another thing I gathered from your explanation is that keeping the water temperature high enough could speed up (or at least prevent slowing down) the parasite’s maturation process, ensuring that there are no viable parasites left to attach to my fish when I reintroduce it.

Would this approach work? If so, is there anything you would recommend improving?

Medication for fish is hard to find locally in my country, but I can get basic treatments like methylene blue.

 

[Fishfur]

Sorry if I got something wrong—it was a lot to take in, and English isn’t my first language.

From what I understood, I could remove the fish from the tank for at least seven days and monitor it in a quarantine tank without needing to add any medication, except for one to treat potential infections caused by the wounds.

After seven days, I can return my fish to the main tank since the adult parasites will have died due to not finding a host.

Another thing I gathered from your explanation is that keeping the water temperature high enough could speed up (or at least prevent slowing down) the parasite’s maturation process, ensuring that there are no viable parasites left to attach to my fish when I reintroduce it.

Would this approach work? If so, is there anything you would recommend improving?

Medication for fish is hard to find locally in my country, but I can get basic treatments like methylene blue.

Yes, you got it.

If you keep the temperature high, it’ll make the life cycle as short as it can be but if you use seawater strength salinity in the main tank, all the parasites will be killed regardless of life stage and the temperature won’t matter.

Methylene blue applied directly to the wounds left behind will prevent any fungal infection from starting and would hopefully help any bacterial infection in the wound where the anchor may still be embedded.

Catch the fish and apply the MB while it’s in a net out of water. Don’t dilute the MB - use it just as it comes from the bottle. It will only stain damaged areas and will rinse off anywhere else.

Be generous with it - it can’t be overdosed this way, A vet taught me to use it this way a long time ago.

 

[alejandrorod]

Yes, you got it.

If you keep the temperature high, it’ll make the life cycle as short as it can be but if you use seawater strength salinity in the main tank, all the parasites will be killed regardless of life stage and the temperature won’t matter.

Methylene blue applied directly to the wounds left behind will prevent any fungal infection from starting and would hopefully help any bacterial infection in the wound where the anchor may still be embedded.

Catch the fish and apply the MB while it’s in a net out of water. Don’t dilute the MB - use it just as it comes from the bottle. It will only stain damaged areas and will rinse off anywhere else.

Be generous with it - it can’t be overdosed this way, A vet taught me to use it this way a long time ago.

I added the fish to a 5-gallon bucket and placed a sponge filter that I pulled from a HOB in another tank. I primarily use sponge filters as mechanical media for my HOBs so that I always have a seeded sponge available if needed.

I’m going to monitor the fish closely and perform frequent water changes due to the low water volume.

I don’t have methylene blue on hand; the only medication I have is API Super Ick Cure. I read somewhere that it mainly contains methylene blue, but I haven’t been able to confirm this. Could it work to treat the wounds, or should I still buy methylene blue?

 

[Fishfur]

I added the fish to a 5-gallon bucket and placed a sponge filter that I pulled from a HOB in another tank. I primarily use sponge filters as mechanical media for my HOBs so that I always have a seeded sponge available if needed.

I’m going to monitor the fish closely and perform frequent water changes due to the low water volume.

I don’t have methylene blue on hand; the only medication I have is API Super Ick Cure. I read somewhere that it mainly contains methylene blue, but I haven’t been able to confirm this. Could it work to treat the wounds, or should I still buy methylene blue?

API Super Ich Cure is malachite green + nitrofurazone. No MB in it and it can’t be used like MB.

But the nitrofurazone in it might help prevent infection.

Only MB can be used directly on a fish - malachite green is too harsh.

 

[alejandrorod]

API Super Ich Cure is malachite green + nitrofurazone. No MB in it and it can’t be used like MB.

But the nitrofurazone in it might help prevent infection.

Only MB can be used directly on a fish - malachite green is too harsh.

I’m going to use it as intended and closely monitor any wounds. I was going to cancel some plans tomorrow to search my whole city for meds, I'm going to treat it now with Super Ick Cure and in a few days from now I'm also going to buy MB and keep it in stock.

Thanks for all your help, I really owe you one. Do you have any website or social media where I can support you?

 

[3Fishnight]

I’m going to use it as intended and closely monitor any wounds. I was going to cancel some plans tomorrow to search my whole city for meds, I'm going to treat it now with Super Ick Cure and in a few days from now I'm also going to buy MB and keep it in stock.

Thanks for all your help, I really owe you one. Do you have any website or social media where I can support you?

Fishfur is the fish whisperer.

 

[Fishfur]

I’m going to use it as intended and closely monitor any wounds. I was going to cancel some plans tomorrow to search my whole city for meds, I'm going to treat it now with Super Ick Cure and in a few days from now I'm also going to buy MB and keep it in stock.

Thanks for all your help, I really owe you one. Do you have any website or social media where I can support you?

You owe me nothing - happy to help. Pass it on if you feel the need - do someone a kindness.

Fishfur is the fish whisperer.

Very kind of you to say but hardly the case - there’s way too much I don’t know.