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SEACHEM MetroPlex 5g

  • Treats protozoan parasites and anaerobic bacterial diseases
  • Low risk of overdose
  • No impact on bio-filter
  • Can mix with food

Seachem MetroPlex effectively treats fish diseases caused by protozoan and anaerobic bacterial (such as Cryptocaryon, Hexamita, Ichthyophthirius). The medication does not adversely affect the filter bed and can be easily removed with carbon.

Seachem MetroPlex is a gentle medication for treating fish with protozoan and bacterial infections. Safe on filter bed, Seachem MetroPlex can either be dosed into the water or combined with Focus in a medicated food mix.

Seachem MetroPlex helps in treating both internal and external infections regardless of the delivery method. When used in a medicated food mix, it is excellent for treating parasites in tanks that contain invertebrates.

Seachem MetroPlex is a safe medication for fish, and the danger of overdosing is very minimal.

Active ingredients: metronidazole (70%) Inactive ingredients: excipients (30%)


MetroPlex is appropriate for treating a variety of protozoan and anaerobic bacterial diseases of fish. Below are some of the more common diseases treatable with MetroPlex. Be aware that many diseases and infections share similar physical and behavioral symptoms, e.g. clamped fins, lesions, loss of appetite.

Ich (White Spot)

  • Ichthyophthirius (freshwater) / Cryptocaryon (saltwater): Looks like salt sprinkled on the fishs body and fins. Usually accompanied by twitching, flashing, and other signs of stress and irritation. Several parasites are grouped under this name, but the symptoms are almost identical. Ich is among the most common infections of fish, and is entirely treatable with diligence and attention to water quality.
  • Suggested Treatment Period: 14 to 28 days
  • Special Considerations: It is very important with this parasite to maintain the copper concentration for the full treatment period. A drop in the copper concentration will allow the parasite to multiply and reinfect the fish. Due to the nature of this parasite, it is normal for the visible signs of infection to get worse before they get better. The medication is still working, but it takes some time for the salt-like cysts on the fish to clear out. Keep up the treatment and the visible spots should clear soon!

Hole in the Head / Head and Lateral Line Erosion

  • Hexamita spp / Spironucleus vortens: Symptoms include a loss of color, erosion or lesions on the face, head, and body, and stringy white feces. This condition is often caused by an internal parasite, but factors like poor diet, poor water quality, and lack of trace elements will all contribute to this issue.
  • Suggested Treatment Period: 14 days
  • Special Considerations: In freshwater this condition is called Hole in the Head. Research your fish preferred diet and water chemistry to ensure they are being properly duplicated in the aquarium. Consider using a nutrient soak for the food to provide essential vitamins and nutrients to the fish. In saltwater this condition is called Marine Head and Lateral Line Erosion. It can be caused by an internal parasite, but more often these symptoms are connected to nutrient deficiencies or poor water quality. Duplication of the natural environment, proper filtration, and a nutrient-rich diet are all essential to curing this condition in saltwater.


  • Piscinoodinium (freshwater) / Amyloodinium (saltwater): Similar to Ich, but smaller and grey-gold. Most often seen in saltwater, but can occur in freshwater as well. Velvet is less common than Ich, but the treatment is almost identical. We see it more often in saltwater than freshwater.
  • Suggested Treatment Period: 14 to 28 days
  • Special Considerations: Velvet is a photosynthetic parasite - it will help with treatment if you can turn off the lights while the fish are infected.