Saltwater Ich (Cryptocaryon) Life Cycle

• 1. Tomont Stage
  • Trophonts which have burrowed into the gills & formed cysts, protected by gill mucus.
  • Trophonts can live in the cyst embedded in the gills almost indefinitely.
  • No effective treatment at this stage.
• 2. Trophont Stage
  • Tomont cysts have been discharged from the gills.
  • Can survive for 6 to 10 days in the cyst.
  • Hyposalinity (Osmotic Shock) and some chemical treatments are effective in exploding the cyst and Tomites.
• 3. Tomite Stage
  • Parasites (Tomites) discharged from the Tomont cyst and become free swimming.
  • Tomites can survive for 1-2 days before they must find another host.
  • Hyposalinity (Osmotic Shock) treatment effective in exploding the Tomites.
  • Many chemical treatments effective at this stage.
• 4. Trophont Stage
  • Tomites which attached to the fish's gills feed from the host, grow, form a cyst and become dormant.
  • Tomites which attach to the fish's surface feed from the host, grow, detach from the fish and go to the Trophont Stage 2.
  • Hyposalinity (Osmotic Shock) treatment effective in exploding the surface cysts.
  • Some chemicals effective in treatment of surface cysts at this stage.

Most (wild captured) fish carry the Cryptocaryon parasite in the their gills in the Tomont Stage 1.  A vast majority of Saltwater Ich outbreaks occur when new fish are introduced into an aquarium. The stress generated by capture and shipping is one of the main causes of the cysts in the gills being released, generating Trophont Stage 2.

The gill mucus encasing the Cryptocaryon parasite in the Tomont Stage 1 renders most, if not all treatments, virtually ineffective at this stage.

Hyposalinity (Osmotic Shock Therapy) and chemical treatments are most effective when the Tomites (the actual parasites) are most vulnerable, during their free swimming stage. Hyposalinity literally explodes the Cryptocaryon cysts in Trophont Stages 2 & 4, exposing the Tomites to both chemical and further Hyposalinity treatments.