Fish Lice: Argulus Treatment and Removal Guide

**Quick Answer:** Fish lice (Argulus) are flat, disc-shaped parasites visible to the naked eye, looking like moving scales on your fish. Remove manually with tweezers and treat with Trichlorfon or salt dips. Without treatment, heavy infestations can kill fish within weeks.

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What are Fish Lice?

Fish lice (Argulus) are parasitic crustaceans that attach to fish skin and feed on blood and body fluids. They're visible as round, flat, translucent discs (2-5mm) that move across the fish's body. Unlike anchor worms, they can detach and swim to new hosts.

Symptoms

Visible flat parasites on skin

Round, disc-shaped creatures (2-5mm)

Red bite marks where lice feed

Fish rubbing against objects

Jumping or flashing behavior

Red, inflamed areas

Lethargy from blood loss

Secondary infections at bite sites

Identifying Fish Lice

**Appearance:**

Flat, round, disc-shaped

Translucent green/brown color

Two large eyes visible

Can see them moving on fish

Leave red marks when detached

**Common locations:**

Fins (easier to grip)

Behind gills

Base of fins

Any flat body surface

How Fish Get Lice

New fish (especially goldfish/koi)

Pond fish introduced to tanks

Live plants from infected systems

Contaminated equipment

Live food sources

More common in outdoor ponds

Treatment Steps

1. **Manual removal first**:

- Catch fish carefully

- Use tweezers to pluck off lice

- Drop lice in alcohol to kill

- Check entire body

2. **Salt dip treatment**:

- 30g salt per litre water

- Dip fish for 5 minutes

- Watch for distress

- Return to tank

3. **Medicate tank**:

- Trichlorfon-based products ($25-30)

- Blue Planet Fluke & Worm ($18-22)

- API General Cure ($20-25)

- Follow instructions exactly

4. **Repeat treatment** - After 7-10 days to kill hatched eggs.

5. **Clean thoroughly** - Vacuum substrate where eggs settle.

Tank Treatment Protocol

**Week 1:**

Remove visible lice

First medication dose

30% water change before meds

**Week 2:**

Second medication dose

Kill newly hatched lice

Continue monitoring

**Week 3:**

Final treatment if needed

Check all fish carefully

Why Quick Action Matters

Each louse lays 20-100 eggs

Eggs hatch in 3-4 weeks

Population explodes rapidly

Heavy infestations kill fish

Wounds get infected

Prevention

Quarantine new fish 4 weeks

Inspect fish before buying

Treat pond fish preventively

Disinfect nets between uses

Avoid mixing pond/tank fish

Check plants carefully

Natural Predators

Some fish eat lice:

Goldfish (will eat off others)

Some cichlids

Not reliable as sole treatment

When to Worry

Get help if:

Too many lice to remove

Fish weakening rapidly

Multiple fish dying

Severe secondary infections

Lice return after treatment

Recovery Care

Treat wounds with Stress Coat

Watch for fungal infections

Maintain perfect water quality

Feed high-quality food

Monitor for reinfestation

Common Questions

**Can fish lice infest humans?**

No, fish lice are species-specific and cannot parasitize humans. Safe to handle during treatment.

**How quickly do fish lice multiply?**

One female can lay 100 eggs. Full lifecycle is 30-60 days. Infestations can explode within months.

**Will lice eventually leave on their own?**

No, they continue reproducing and feeding until the fish dies or is treated.

**Can I use dog/cat flea treatment?**

Never. These are toxic to fish. Only use aquarium-specific medications.

**Do lice survive without fish?**

Adults die within days without hosts, but eggs can survive weeks waiting to hatch.

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