Medic is a water treatment / parasite control product formulated by PolypLab for both marine and freshwater aquariums.

It is described as a reef-safe oxidizing agent / water conditioner that targets external fish parasites (especially in saltwater systems) without harming invertebrates or beneficial bacteria.

It is particularly marketed as effective against:

• Marine Ich (Cryptocaryon irritans)
• Freshwater Ich (Ichthyophthirius)
• Marine Velvet (Amyloodinium ocellatum)

Mode of Action for Medic by Polyp Lab 30 ml

• Medic contains oxidizing agents (often “crystallized peroxide salts”) as the active ingredient(s)

• Many external parasites (protozoans) have life cycles with distinct stages: attached (trophonts), reproductive (tomonts), free-swimming (theronts/dinospores). Medic’s formulation aims not only to affect the attached stage (trophonts) but also disrupt the life cycle in the free-swimming stage, making it more effective in preventing re-infection.

• Because of this, maintaining a relatively constant effective concentration over the parasite’s hatching / infective window is important.

• It is “buffered to physiological pH,” meaning the formulation is intended not to shock pH or alkalinity significantly when dosed.

• It is claimed not to damage invertebrates (e.g. corals, shrimp) and not to harm nitrifying bacteria (the beneficial bacteria in filtration).

Instructions of Medic

The standard dosage is one level scoop for every 190 liters (about 50 gallons) of total system water volume, added twice per day — once in the morning and once in the evening. In severe infestations, the dosage can be increased up to three scoops per 190 liters, still given twice daily. A treatment course should last for at least 10 consecutive days. If the outbreak is more serious, the treatment period can be extended to a maximum of 20 days.

During treatment, you should keep protein skimmers running, but turn off ozone and activated carbon because they will neutralize the active ingredients. UV sterilizers should also be off during dosing and may be switched back on roughly an hour afterward if needed. It is essential to maintain consistent dosing throughout the full course, even if fish appear to recover before the 10–20 days are complete. Stopping too early can allow the parasite’s life cycle to continue and cause reinfection.

Once the treatment period is finished, it’s recommended to run fresh activated carbon for two to three days to remove any remaining traces of Medic from the water.

Advantages

• Because Medic is reef-safe, it is often used in systems containing corals and invertebrates where many conventional treatments (e.g. copper-based) would be contraindicated.

• By targeting the free-swimming infective stage, it aims to break the parasite life cycle more efficiently than treatments that only act on attached stages.

• Its buffered nature reduces the risk of pH shock when dosing.

• It is marketed as non-disruptive to nitrifying bacteria (i.e. it should not significantly impair biological filtration).

Risks

• As with any chemical treatment, overdosing can be dangerous. Although many sources do not explicitly state a limit, caution is always warranted.

• In smaller systems (e.g. nano reefs), even modest dosing errors may lead to stress on livestock.

• The presence of ozone, activated carbon, or UV (used at the wrong time) can neutralize or degrade the active oxidizing agents, reducing efficacy.

• The product’s effectiveness depends on consistent dosing across the entire treatment window; missing doses or shortening the regimen can allow re-infection.

• While marketed as safe to invertebrates and bacteria, real-world results may vary—some sensitive species may still suffer, and water chemistry fluctuations (e.g. pH, oxygen) could stress livestock.

Medic (PolypLab 30 mL) is a specialized, reef-safe oxidizing water conditioner and antiparasitic treatment formulated to address external fish parasites (e.g. Ich, Velvet) in both marine and freshwater environments. Its strengths lie in being safer (for corals and filter bacteria) than many traditional parasite treatments, and in targeting multiple life stages of parasites, including the free-swimming infective stage.

When used correctly — with precise dosing, a full treatment schedule (10–20 days), and careful avoidance of interfering equipment (ozone, carbon) — it can be an effective option for treating parasite outbreaks in reef systems. However, care must be taken not to overdo it, and one should always monitor livestock behavior and water parameters during treatment.