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Parasitic Diseases

PARASITIC DISEASES

ICH / White Spot (Ichthyophthirius multifiliis) — Freshwater

Symptoms: White salt- or semolina-like granules on the body and fins; rubbing against objects; affected gills Cause: Obligate ciliated protozoan Life cycle: The parasite (trophont) lives inside the fish → falls to the bottom (tomont) → divides into hundreds of tomites → which swim in search of a new host. The treatment kills only the swimming tomites—not the parasite inside the fish.

Treatment:

  • High temperature: raising the temperature to 30°C speeds up the cycle (2–3 times) → the cycle ends faster
  • Sodium chloride (salt): 2–3 g/L in freshwater — not for salt-sensitive fish (Corydoras, softwater tetras)
  • Malachite green + formalin (a common ich treatment): effective but toxic to fish in excessive amounts
  • Formalin (37% diluted formaldehyde): very effective, toxic; use with proper ventilation
  • Combined stress: temperature + salt is the least toxic option

Without a quarantine tank: The cyst (tomont) survives in the aquarium for up to 3 weeks without a host → keeping the aquarium "fish-free" for 3–4 weeks at a high temperature (>28°C) can sanitize the aquarium.

Velvet (Oodinium pilularis) — Freshwater

Symptoms: Very fine golden/grayish powder (like velvet), smaller than ich, intense scratching, gills affected first, rapid breathing Cause: Parasitic dinoflagellate Significance: Much more dangerous and fast-spreading than ich. It kills fish within days.

Treatment:

  • Total darkness + high temperature: Photosynthetic Oodinium → cannot survive well without light
  • Copper sulfate (with measuring device): the most effective
  • Sodium chloride (salt): helps
  • Specific medications (eSHa EXIT, JBL Punktol Ultra)
  • Quarantine: An aquarium without fish needs to be kept in the dark for 4 weeks

Ich Marino (Cryptocaryon irritans) — Saltwater

Similar to freshwater ich, but:

  • Much longer cycle (up to 28 days)
  • It is NOT killed by heat or salt (it is a marine species)
  • Copper Treatment (Chelated Copper) in Quarantine: Cupramine, CopperPower, Copper Power
  • The main fishless aquarium needs to remain empty for 8–10 weeks so that the parasite dies without a host.
  • NEVER use copper in an aquarium with live rock, corals, or invertebrates—copper accumulates in the rock and is impossible to remove

Copper-free alternative:

  • Hyposalinity (reducing salinity to 1.009–1.010) for 4–6 weeks in quarantine
  • Fish can tolerate it, but the parasite cannot

Marine Velvet (Amyloodinium ocellatum)

The Most Dangerous Thing at Sea

  • It is fatal within 24–72 hours if left untreated
  • Symptoms: golden powder, affected gills, gasping
  • Treatment: Chelated copper; immediate quarantine
  • Also sensitive to low pH during quarantine (pH 8.3 → lowering it to 7.8–8.0 may help)

Anchor Worm (Lernaea cyprinacea)

Symptoms: Visible reddish worms attached to the body, with swelling around the area Cause: External parasitic copepod Treatment:

  • Manual removal with tweezers (by twisting the parasite)
  • Treat the wound with an antiseptic
  • Dipterex (trichlorfon) / DIMILIN in water
  • Frequent water changes eliminate swimming larvae

Chilodonella (Chilodonella spp.)

Symptoms: Grayish skin, excessive mucus, affected gills, fish gasping at the surface More dangerous at low temperatures (cold water) Treatment: Salt, malachite green, formalin, fenbendazole

Tricodina (Trichodina spp.)

Symptoms: Itching, excessive mucus, reddened skin Treatment: Salt (2–3 g/L), malachite green

BACTERIAL DISEASES