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Uronema marinum

Classification: Ciliated protozoan (class Oligohymenophorea) Water: Exclusively seawater Symptoms:

  • Red or whitish sores on the skin — the parasite invades the tissues
  • Subcutaneous hemorrhages (red spots)
  • Skin that peels off or looks "rotten"
  • Rapid weight loss and loss of appetite
  • Panting, abnormal behavior
  • Very high mortality rate within a few days Organisms most affected: Any marine fish, especially those that are weakened. Very common in fish that arrive stressed from transport. Differential diagnosis: Ulcers are a key indicator—Ich causes spots, Velvet causes a powdery coating, and Uronema causes irregular, bleeding ulcers. The fish looks as if it has been "eaten from the inside." Life Cycle: A free-living ciliate that becomes an opportunistic parasite when the fish is weakened. It feeds on bacteria, but can invade the tissues of stressed fish.

Treatment:

  • Formalin: Similar to Brooklynella, this is the most effective treatment. Soak for 30–60 minutes.
  • Metronidazole: Administered in medicated food or water may help.
  • Chelated copper: Less effective than Ich, but can be used in combination with it.
  • Freshwater dip: Helps eliminate superficial parasites.
  • The key is to act VERY quickly—Uronema can be fatal within 24–48 hours. Prevention: Quarantine all new fish for 4–6 weeks. Minimize stress during transport. Do not introduce fish that are already weakened directly into the tank.

Monogeneans / Monogenean Flukes (Benedenia, Neobenedenia, Gyrodactylus, Dactylogyrus)

Classification: Monogenetic platyhelminths (flatworms) Water: Freshwater and seawater (different genera) General symptoms:

  • Intense and frequent scratching against any surface
  • Excess mucus on the skin and gills
  • Erratic behavior, jumping
  • Eye Opacity (Ocular Monogenea)
  • Swollen or necrotic gills (gill-bearing fish)
  • In freshwater: breathing at the surface, fins close to the body Main types:
  • Benedenia / Neobenedenia (marine): On the skin and eyes. Visible to the naked eye (1–4 mm) as white, oval spots.
  • Gyrodactylus (freshwater and marine): Found on the skin and fins. Microscopic. Viviparous (they reproduce directly inside the fish).
  • Dactylogyrus (primarily found in freshwater): Found in the gills. Oviparous. Microscopic.

Diagnosis: Skin or mucosal scraping and microscopic examination. In Benedenia, it is sometimes visible to the naked eye. Strong evidence is provided by intense scratching and excessive mucus.

Freshwater treatment:

  • Praziquantel: 2–5 mg/L for 2–3 days during quarantine. Repeat after 7 days to target Dactylogyrus eggs. Safe for shrimp at low doses.
  • Formaldehyde + malachite green: Effective, but more toxic.
  • Sal: Help with Gyrodactylus.

Marine treatment:

  • Praziquantel: Effective against Benedenia and Neobenedenia. Higher dose (10 mg/L) during quarantine.
  • Freshwater dip: Very effective for killing skin monogeneans in marine fish (osmotic salinity difference).
  • Metronidazole: Less effective for monogeneans.

Vorticella and Epistylis

Classification: Sessile ciliated protozoa (Peritrichia) Water: Mainly freshwater; also seawater Symptoms:

  • Small white tufts visible on the skin, fins, and gills
  • Sore throat, excess mucus
  • More common in shrimp and freshwater fish
  • It can be mistaken for a fungal infection Cause: Opportunistic in water with excess organic matter (suspended bacteria)

Treatment: