How to Get Rid of Lice and Anchor Worm Without Killing my Fish?

Q. I have a one-year-old flowerhorn which I keep in a four-foot tank. Recently, it developed a pimple-like spot on the top of its tail (near the body). It feels hard to the touch. I have tried to treat the problem by using Ocean Free external fungus and changing the water every four days. I’ve also tried Ocean Free slime, white spot and velvet away, but to no avail. Now, I’ve discovered some white cotton-like growth around the ‘pimple.’ Should I take the fish out of the water and clean up the spot?

Although it is quite difficult to tell exactly what it is without actual examination, my guess is that the problem is caused by external parasites.The two common types of parasites usually found among aquarium fishes are:

• Fish Lice: These are circular in shape and measure about 5 mm across. If you observe them carefully over a period of time, these circular discs will move about on the fish body. They irritate as well as extract nutrients from the fish.
• Anchor Worm: In its adulthood stage, you can detect it as a pimple-shaped object with a “tail,” measuring about ¾ cm long, sticking out from it. This “tail” is actually the anchor worm itself.

These external parasites do not move about. They anchor themselves to one spot, and the swelling develops around the anchor point, and this is only obvious in the finnage area.

Look carefully at the “pimple” growth on your fish. Does it have a tail? If it does, then I would recommend that you first salt the water to at least 0.3% level, then dose it with a good external parasitic medication.

Parasite Clear or Clout is highly effective against anchor worms. I would also suggest that you dose half the recommended strength, and then make sure that your fish does not become unduly stressed before adding the full dosage.

Please be warned though, that anchor worm infestation takes a long time to be completely eradicated. You’ll probably need to dose two cycles to destroy all traces of it.

If you do not see any “tail” on this pimple-shaped growth, then the problem is an indication of poor quality water. I won’t suggest that you change at least 50 per cent of the water. Wait till the following day, and bring the salt level up to 0.3%.

Get a bottle of transmore (or finquel) and potassium permanganate. Transfer your fish into a bowl and slowly add the transmore into it until your fish appear lifeless. Be careful NOT to add too much transmore, otherwise your fish will sleep forever!

Prepare a clean towel and soak it in the same bowl of water before laying it out on a flat surface. Quickly lay the fish on the towel, and using either your fingernail or a flat object, scrape off the “pimple” and fungus. Then dab the scraped area with potassium permanganate. Be very careful not to get any of this into the gills, as it will oxidize the delicate gill filaments.

Return the fish to the tank and increase the aeration until the fish is swimming upright. Feed it sparingly over the next few days. This should do the trick. If you are nervous about carrying out this procedure, get an experienced friend to guide you along. Otherwise, leave the “pimple” alone, and just treat the fungus with an anti-fungus medication. And oh yes, do remember to clean your fingernails thoroughly after the “operation!”

Note of caution: You can buy potassium permanganate in pharmacy. As it is highly caustic, please use extra care. Avoid getting it into your eyes and the fish’s eyes. Use cotton wool to apply it. It is an effective antiseptic and oxidizing agent. As for transmore, it is a “sleeping” agent which you can buy from any aquarium. It is commonly used in small doses as a tranquilizer for arowanas when they are being transported.

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