Top 12 Saltwater Fish Diseases and Their Reef-Safe Treatments

I wanted to make a list of the top 12 saltwater diseases, the medications and herbal remedies that can be used in the display tank, and whether these are safe for corals, anemones, and invertebrates. Where applicable, step-by-step dosage instructions are provided for each treatment, including the use of hydrogen peroxide as an alternative treatment.

1. Marine Ich (Cryptocaryon irritans)

• Reef-Safe Medications:

  • MetroPlex (Seachem): Effective when soaked into food.
    • Dosage: 1 scoop mixed with food, feed daily.
    • Duration: 7-10 days.
    • Important Note: It cannot be added to the water directly and it must be mixed in food. 

• Herbal Remedies:

  • Herbal Ich Attack (Microbe-Lift): A natural remedy for Ich and other external parasites.
    • Dosage: 1 teaspoon per 10 gallons daily until symptoms subside.
  • Garlic Guard (Seachem): Boosts immune function.
  • Garlic Xtreme (Kent Marine): Helps fish resist infection and boosts appetite.
  • Herbtana: Is a unique, herbal, immune-enhancing stimulant
  • Kordon Ich Attack: A herbal-based treatment designed to eliminate Ich.
    • Dosage: 1 teaspoon per 10 gallons daily.
    • Duration: Continue until symptoms subside.

• Alternative Treatment:

  • Hydrogen Peroxide

    • Direct Tank Treatment: Hydrogen peroxide can be used at lower concentrations for display tanks.
      • Dosage: Add 2-3 ml of 3% hydrogen peroxide per 10 gallons of water.
      • Duration: Repeat every 3-4 days as needed. Ensure increased aeration during treatment to maintain oxygen levels.

• Supportive Care:

  • UV Sterilizer: Reduces free-swimming parasites.
  • Increased Aeration: Helps with respiratory stress.
  • Pristine Water Quality: Prevents additional stress and boosts the immune system.

• Is This a Complete Treatment?
  No. Herbal Ich Attack, Kordon Ich Attack, and MetroPlex help, but severe cases may require quarantine with copper-based treatments.

Read More About Marine Ich Here

2. Marine Velvet (Amyloodinium ocellatum)

• Reef-Safe Medications:

  • Polyplab Medic: Useful for early Velvet infections.
    • Dosage: 1 scoop per 10 gallons daily.
    • Duration: Continue for 10-14 days.
  • Ruby Reef Rally Pro: Short-term use for Velvet and bacterial infections.
    • Dosage: 1 oz per 10 gallons every 24 hours.
    • Duration: 3 consecutive days.

• Herbal Remedies:

  • Garlic Guard (Seachem): Immune booster for Velvet infections.

  • Herbal Ich Attack (Microbe-Lift): May provide partial relief but not sufficient for advanced cases.
  • Herbtana: Is a unique, herbal, immune-enhancing stimulant
  • Kordon Ich Attack: Some hobbyists report partial success using Kordon Ich Attack for Velvet.

• Alternative Treatment:

  • Hydrogen Peroxide:

    • Direct Tank Treatment: In cases of widespread Velvet, hydrogen peroxide may help reduce parasites.
      • Dosage: Add 2-3 ml of 3% hydrogen peroxide per 10 gallons.
      • Duration: Repeat every 3-4 days if needed.

• Supportive Care:

  • UV Sterilizer: Controls free-swimming parasites.
  • Increased Oxygenation: Velvet reduces respiratory efficiency.
  • Dim Lighting: Slows parasite activity and reduces stress.

• Is This a Complete Treatment?
  No. Velvet often requires copper or chloroquine in a quarantine tank.

Read More About Marine Velvet Here

3. Brooklynella (Brooklynella hostilis)

• Reef-Safe Medications:

  • MetroPlex (Seachem): Effective when used with food.
    • Dosage: 1 scoop per tablespoon of food.
    • Duration: 7-10 days.

• Herbal Remedies:

  • Garlic Guard (Seachem): Supports immune function and supports appetite.
  • Herbal Ich Attack (Microbe-Lift): Can assist with treatment but is not sufficient alone.
  • Kordon Ich Attack: May assist but is generally not considered effective for severe Brooklynella infections.

• Alternative Treatment:

  • Hydrogen Peroxide

    • Direct Tank Treatment: Peroxide may reduce external parasites in mild cases.
      • Dosage: 2-3 ml of 3% hydrogen peroxide per 10 gallons of water.
      • Duration: Every 3-4 days with proper aeration.

• Supportive Care:

  • Increased Oxygenation: Vital for managing gill damage caused by Brooklynella.
  • Vitamin-Enhanced Foods: Aid in boosting the immune response and speeding up recovery.

• Is This a Complete Treatment?
  No. Quarantine treatment with copper or formalin is needed for severe infections.

Read More about Brooklynella Here

4. Uronema

• Reef-Safe Medications:
  None. Uronema requires aggressive treatments that are not safe for reef tanks.

• Herbal Remedies:

  • Garlic Guard (Seachem): Provides immune support, though not a cure for Uronema.

• Alternative Treatment

  • Hydrogen Peroxide

    • Dosage: 2-3 ml of 3% hydrogen peroxide per 10 gallons of water.
    • Duration: Repeat every 3-4 days if needed.

• Supportive Care:

  • UV Sterilizer: Helps reduce parasite load.
  • Maintain Pristine Water Quality: Reduces stress, helping fish manage the infection.

• Is This a Complete Treatment?
  No. Uronema cannot be fully treated in a reef tank; fish must be moved to a quarantine tank.

Read More About Uronema Here

5. Flukes (Monogenean Parasites)

• Reef-Safe Medications:

  • PraziPro (Hikari): Safe for use in reef tanks and highly effective against flukes.
    • Dosage: 1 teaspoon per 20 gallons.
    • Important Note: Exercise caution with invertebrates, particularly feather dusters, which are sensitive to PraziPro.

• Herbal Remedies:

  • Garlic Extract: Can support the immune system but won't eliminate flukes.
  • Herbtana: Is a unique, herbal, immune-enhancing stimulant

• Supportive Care:

  • Freshwater Dips: A 5-minute dip can remove external flukes temporarily.
  • UV Sterilizer: Controls the larval stage of flukes.

• Is This a Complete Treatment?
  Yes. PraziPro is a reliable treatment for flukes in reef tanks.

Read More About Flukes Here

6. Fin Rot (Bacterial Infection)

• Reef-Safe Medications:

  • None

• Herbal Remedies:

  • Melafix (API): A natural remedy derived from tea tree oil.

    • Dosage: 5 mL per 10 gallons of water daily.
    • Duration: 7 days.

• Supportive Care:

  • Pristine Water Quality: Prevents further bacterial infections.
  • Increased Protein Skimming: Reduces organic waste that may fuel bacterial growth.

• Is This a Complete Treatment?
  Yes. Melafix can effectively treat mild to moderate fin rot.

Read More About Fin Rot Here

7. Popeye (Exophthalmia)

• Reef-Safe Medications:

  • None

• Herbal Remedies:

  • None.

• Alternative Treatment
  • Epsom Salt: Reduces swelling associated with Popeye.
    • Dosage: 1 tablespoon per 5 gallons of water.
    • Duration: 3-5 days.

• Supportive Care:

  • Vitamin-Enhanced Foods: Supports immune function.
  • Water Quality Management: Ensures that secondary infections do not take hold.

• Is This a Complete Treatment?
  No. Epsom salt reduces swelling but may not treat the underlying cause.

Read More About Popeye Here

8. Head and Lateral Line Erosion (HLLE) 

• Reef-Safe Medications:
  None, as HLLE is usually caused by poor diet, stress, or environmental factors.

• Herbal Remedies:

  • Garlic Guard (Seachem): Supports the immune system.
  • Vitamin Supplements: Selcon and similar products boost fish immunity and overall health.

• Supportive Care:

  • Nutritional Improvements: Provide vitamin-rich foods, especially Vitamin C, and other essential nutrients.
  • Check for Stray Voltage: Electrical issues can contribute to HLLE, so ensure that there are no stray currents in the tank.
  • Pristine Water Quality: Clean water conditions promote recovery and prevent further damage.

• Is This a Complete Treatment?
  No. Treatment focuses on improving environmental conditions and nutrition.

Read More About HLLE Here

9. Internal Parasites (Nematodes, Worms)

• Reef-Safe Medications:

  • PraziPro (Hikari): Effective when soaked in food.
    • Dosage: Soak food in PraziPro for 15-30 minutes before feeding.
    • Duration: Feed medicated food for 7-10 days.
    • Important Note: Use caution when dosing PraziPro around invertebrates, particularly feather dusters, as they are highly sensitive to the medication.
  • MetroPlex (Seachem): Soak food with MetroPlex to treat internal parasites.
    • Dosage: 1 scoop mixed with food.
    • Duration: 7-10 days.

• Herbal Remedies:

  • Garlic Guard (Seachem): Helps support the immune system and assists in fighting parasites.

• Supportive Care:

  • Maintain Pristine Water Quality: Keeping the water parameters stable reduces stress and supports the immune system, aiding the fish's ability to fight off the parasites.
  • Nutritional Support: Feed fish high-quality, vitamin-enriched foods to enhance their resistance to internal parasites.

• Is This a Complete Treatment?
  Yes. PraziPro and MetroPlex, when soaked in food, are effective for treating internal parasites.

Read More About Internal Parasites Here

10. Bacterial Infections

• Reef-Safe Medications:

• • Ruby Reef Rally Pro: Effective for mild bacterial infections.
    • Dosage: 1 oz per 10 gallons daily.
    • Duration: 3 consecutive days.

• Herbal Remedies:

  • Melafix (API): A natural remedy that is effective for mild bacterial infections.
    • Dosage: 5 mL per 10 gallons of water daily.
    • Duration: 7-10 days.

• Supportive Care:

  • Increased Aeration: Helps prevent respiratory issues caused by bacterial infections.
  • UV Sterilizer: Reduces free-floating bacteria in the water column, helping prevent the spread of the infection.

• Is This a Complete Treatment?
  Yes. Melafix and Ruby Reef Rally Pro, combined with supportive care, can effectively treat bacterial infections in most cases.

Read More About Bacterial Infections Here

11. Lymphocystis (Viral Disease)

• Reef-Safe Medications:

  • None. Lymphocystis is a viral disease that does not respond to medications.

• Herbal Remedies:

  • Garlic Guard (Seachem): Supports the immune system, helping fish recover from viral infections.
  • Vitamin Supplements: Provide additional nutrition to boost immune responses.

• Supportive Care:

  • Pristine Water Quality: Maintaining excellent water conditions reduces stress and prevents the disease from worsening.
  • Good Nutrition: Boosting the immune system through a nutrient-rich diet is key to managing viral infections.
  • UV Sterilizer: Reduces the spread of the virus in the tank, though it does not eliminate the infection.

• Is This a Complete Treatment?
  No. Since no direct treatment exists for Lymphocystis, care focuses on improving immune response and environmental conditions.

Read More About Lymphocystis Here

12. Fungal Infections (Saprolegnia)

• Reef-Safe Medications:

  • None

• Herbal Remedies:

  • Melafix (API): Effective for fungal infections.
    • Dosage: 5 mL per 10 gallons daily.
    • Duration: 7-10 days

• Supportive Care:

  • Pristine Water Quality: Prevents further fungal growth and promotes recovery.
  • Increased Aeration: Ensures good oxygenation, which helps fish fight off infections.

• Is This a Complete Treatment?
  Yes. Melafix combined with supportive care, can effectively treat fungal infections.

Read More About Fungal Infections Here

Medication and Herbal Remedies Chart

Medications/Herbal Remedies

1. Brightwell Aquatics Garlic Power

   • Company: Brightwell Aquatics
   • Target: Immune support and parasite resistance
   • Website: Brightwell Garlic Power

2. GarlicGuard

   • Company: Seachem (GarlicGuard)
   • Target: Immune system support, parasite resistance
   • Website: Seachem GarlicGuard
3. Herbtana Microlift
   • Company: MicroLift
   • Target: Marine Ich, Marine Velvet, parasites, flukes
   • Website: Herbtana

4. Kordon Herbal Ich Attack

   • Company: Kordon
   • Target: Marine Ich, external parasites
   • Website: Kordon Herbal Ich Attack

5. Melafix

   • Company: API
   • Target: Mild bacterial infections, fin rot
   • Website: API Melafix

6. Metroplex

   • Company: Seachem
   • Target: Internal parasites, protozoa (Hexamita), anaerobic bacteria
   • Website: Seachem Metroplex

7. PraziPro

   • Company: Hikari
   • Target: Flukes, flatworms, external parasites
   • Website: Hikari PraziPro

8. Polyplab Medic

   • Company: Polyplab
   • Target: Marine Ich and other parasites
   • Website: Polyplab Medic

9. Ruby Reef Kick-Ich

   • Company: Ruby Reef
   • Target: Marine Ich
   • Website: Ruby Reef Kick-Ich

10. Ruby Reef Rally Pro

    • Company: Ruby Reef
    • Target: Marine Velvet, Brooklynella, Uronema, bacterial infections
    • Website: Ruby Reef Rally Pro
11. Selcon
    • Company: American Marine
    • Target: Concentrate contains Omega-3 HUFA, Vitamin B12 and pure stabilized Vitamin C
    • Website: American Marine Selcon

 Supportive Care in Reef Tanks

For many saltwater diseases, supportive care plays a crucial role in helping your fish recover, especially when reef-safe medications are limited. Here’s how to support your fish while protecting corals and invertebrates:

• UV Sterilization: UV sterilizers help reduce free-swimming pathogens like parasites, viruses, and bacteria. This is especially useful in managing diseases like Marine Ich, Velvet, and Brooklynella.

• Increased Aeration: Many diseases, particularly parasitic infections, affect the gills, leading to respiratory distress. Increasing aeration or oxygenation in the tank helps fish breathe more easily and recover more quickly.

• Vitamin-Enhanced Foods: Using supplements like Selcon boosts the fish’s immune system, helping them resist infections and recover faster. Providing a high-quality, nutrient-rich diet is essential to aid recovery from any disease.

• Water Quality Management: Maintaining stable water conditions with regular water changes, effective filtration, and protein skimming reduces stress and keeps the tank inhabitants healthy. Consistent testing of water parameters helps you spot and correct any imbalances that could exacerbate diseases.

Common Myths

1. Myth: "Reef-Safe" Means Completely Safe for All Invertebrates and Corals

   • Reality: Not all medications labeled "reef-safe" are safe for every type of coral, invertebrate, or anemone. For example, PraziPro is generally safe, but it can harm feather dusters and some delicate invertebrates. Always check the specific compatibility with your tank inhabitants before using any medication, even if it’s labeled "reef-safe."

2. Myth: Herbal Remedies Are Always Safe for Reef Tanks

   • Reality: Herbal remedies, like tea tree oil and garlic extract, can be milder alternatives to chemical medications, but they are not always 100% safe for sensitive reef systems. Overuse or incorrect dosing can stress corals and invertebrates. It's essential to monitor your tank closely when using any treatment.

3. Myth: You Can Use Any Type of Garlic for Fish Health

   • Reality: Only use aquarium-specific garlic products designed for marine tanks. Adding raw garlic or garlic intended for human consumption can introduce contaminants and unwanted additives to your tank.

4. Myth: Hydrogen Peroxide Will Kill All Diseases and Parasites in the Display Tank

   • Reality: While hydrogen peroxide can be effective against algae blooms and certain parasites when used properly, it is not a cure-all. It is best used as a supplemental treatment or for specific issues, and overdosing can harm fish, invertebrates, and corals.

5. Myth: Frequent Use of Antibiotics in Reef Tanks Won't Harm Biological Filtration

   • Reality: Prolonged or excessive use of antibiotics such as Kanaplex or Metronidazole can impact your tank's beneficial bacteria, which are critical for maintaining water quality. Always follow the proper dosage and duration guidelines and monitor water parameters closely.

FAQ's

1. Can I treat diseases in my display tank without harming my corals or invertebrates?

   • Yes, several reef-safe medications are available, such as PraziPro (with caution around feather dusters), Herbal Ich Attack, and Melafix. Always check the specific product compatibility with your tank inhabitants before treatment.

2. Can I use tea tree oil directly in my tank to treat bacterial infections?

   • Yes, but it is safer to use commercial preparations like Melafix, which contains tea tree oil. The recommended dosage is 5 mL per 10 gallons for 7 days. It’s effective for mild bacterial infections and generally safe for most reef systems when used correctly.

3. Is garlic extract effective against parasites in saltwater tanks?

   • Garlic has always been controversial in the saltwater hobby. Garlic extract is often used to boost fish immune systems and can help fish resist parasitic infections, but it is not a stand-alone cure for diseases like Marine Ich or Velvet. It should be used alongside other treatments. There is no proof that adding garlic helps, but many hobbyists swear by it.

4. Is hydrogen peroxide safe for use in my display tank?

   • Hydrogen peroxide can be used in low concentrations (2-3 mL of 3% hydrogen peroxide per 10 gallons) for algae control or specific infections. However, it can reduce oxygen levels temporarily, so ensure proper aeration and avoid overuse.

5. How can I treat Marine Velvet in a reef tank?

   • Unfortunately, there are no fully reef-safe medications for Marine Velvet. The best course of action is to move the infected fish to a quarantine tank and treat with copper or chloroquine phosphate. In the display tank, supportive care measures like UV sterilization and increased oxygenation can help manage the outbreak.

6. Can I combine herbal remedies with chemical medications in the tank?

   • It depends on the specific treatments. Garlic extract and Herbal Ich Attack are often used alongside other medications like Metroplex or PraziPro, but always ensure you are not overdosing or causing unnecessary stress to your fish or invertebrates.

7. What’s the best way to prevent disease outbreaks in my reef tank?

   • The best prevention is a combination of quarantining new arrivals, maintaining pristine water quality, and providing a nutrient-rich diet. Using supplements like garlic extract or vitamin-enriched foods can also help boost fish immunity.

8. Can reef-safe medications affect my tank’s biological filtration?

   • Yes, even some reef-safe medications, especially antibiotics like Metroplex or Kanaplex, can harm beneficial bacteria over time. Monitor your water parameters closely and be cautious of prolonged use.

9. Should I turn off my protein skimmer or UV sterilizer while treating with herbal remedies or medications?

   • For products like Melafix, you should reduce or turn off the protein skimmer temporarily to prevent excessive foaming. Some medications may also require turning off UV sterilizers to avoid degrading the treatment’s active ingredients. Always check the product’s instructions for guidance.

Conclusion

Successfully treating diseases in a reef tank requires balancing effective disease management with the safety of your corals, invertebrates, and other sensitive organisms. By utilizing reef-safe medications, herbal remedies, and focusing on supportive care, you can help your fish recover from common saltwater diseases while keeping your reef inhabitants safe. Always remember to monitor your tank closely during treatment and follow dosage instructions carefully to avoid harming your delicate reef ecosystem.

Happy Reefing!