Hikari PraziPro is a liquid praziquantel formulation sold as an over-the-counter aquarium antiparasitic. Praziquantel is one of the safest and most effective antiparasitic compounds available to hobbyists for treating flukes (monogenean and digenean trematodes), tapeworms (cestodes), and some other invertebrate parasites. A key advantage of PraziPro is that it is considered safe for invertebrates, corals, and live plants at recommended doses, making it one of the few aquarium medications suitable for reef tanks. PraziPro is an OTC aquarium product; veterinary-grade praziquantel is also available. For valuable fish, consult an aquatic veterinarian for guidance.

Overview

Praziquantel is an anthelmintic that acts on parasite muscle membranes, causing paralysis, detachment, and death. It has been used in human and veterinary medicine for decades against tapeworms and flukes and has an excellent safety profile in fish. PraziPro delivers praziquantel in a water-soluble liquid form that can be dosed directly into the aquarium.

Uses

  • Gill and skin flukes (Dactylogyrus, Gyrodactylus)
  • Monogenean trematodes in marine fish (very common in wild-caught species)
  • Tapeworms (intestinal cestodes)
  • Planaria (flatworm pests in shrimp tanks — with caution for shrimp)
  • Quarantine protocols for newly purchased marine fish
  • Turbellarian flatworm infestations

PraziPro is not effective against protozoan parasites such as ich, velvet, or hexamita — use appropriate medications for those conditions.

Dosage

  • Standard dose: 1 teaspoon (5 mL) per 20 gallons of water
  • Duration: Single dose for 5 to 7 days, repeat after 3 to 4 weeks to catch newly hatched parasites
  • Reef and invertebrate tanks: Standard dose is considered safe for most inverts, but monitor closely
  • Water changes before redosing are recommended to maintain water quality

Follow the product label for exact dosing, which is the definitive reference.

Safety Considerations

  • Invertebrate-safe — Generally safe for shrimp, snails, corals, and most reef inhabitants at label dose. Some sensitive species may show stress; monitor closely.
  • Scaleless fish — PraziPro is considered safe for scaleless fish at standard dose, unlike many other antiparasitic treatments
  • Reef tanks — Can be used in reef displays without harming corals or most beneficial organisms, though feather dusters and some other worms may be affected
  • Oxygenation — PraziPro foams when agitated. Reduce surface agitation temporarily if foaming becomes excessive. Oxygen levels may drop slightly during treatment.
  • Egg-laying fish — Some species may be sensitive during spawning
  • Dinoflagellate sensitivity — Rarely, marine tanks may show reduced dinoflagellates after PraziPro

Water Chemistry Effects

  • Minimal effect on pH, hardness, or salinity
  • Causes visible foaming, especially in protein-skimmed marine systems. Turn off protein skimmers during treatment or they may overflow.
  • Activated carbon will remove praziquantel. Remove carbon during treatment.
  • Treatment residues can be removed with carbon after the treatment period

How to Use

  1. Calculate total aquarium volume accurately
  2. Remove activated carbon from the filter
  3. Turn off protein skimmers (they will foam excessively)
  4. Shake the bottle well
  5. Add the correct dose directly to an area of good flow
  6. Leave in the tank for 5 to 7 days
  7. Perform a water change and return activated carbon after treatment
  8. Repeat treatment after 3 to 4 weeks to catch newly hatched flukes

FAQs

Is PraziPro reef-safe? Yes, it is generally considered safe for reef tanks at label dose, making it one of the most commonly used medications for quarantining new marine fish.

Will it kill my snails or shrimp? At label dose, snails and most shrimp are unaffected. Some keepers report sensitivity in delicate dwarf shrimp, so monitor closely.

Does it treat ich or velvet? No. Praziquantel does not work against protozoan parasites.

How often should I redose? A second treatment 3 to 4 weeks after the first catches flukes that have hatched from eggs laid before the first dose.

Can I use it with other medications? PraziPro is often combined with other treatments in quarantine protocols, but always research compatibility before layering medications.