Medication reference

A great place to start when you don't know what's wrong and can't get a skin scrape. Use plain salt with no additives, and weigh it (1 level tsp ≈ 5 g). Dosage range: 0.1%–0.6% (1–6 g per liter ≈ 3.8–22.7 g per gallon) for in-tank treatment; the 3% dip is separate.

1. Light supportive salinity, 0.1% (1 ppt): 1 g per liter (≈3.8 g per gallon). For hospital tanks, slime support with flukes, alongside a labeled antimicrobial course, a one-sided eye bulge after a bump, and cuts or secondary infection risk.
2. Ammonia burns: a 48-hour salt and water-change trial.
3. 0.3% to reduce osmoregulatory stress (3 ppt): 3 g per liter (≈11.4 g per gallon). Also used for some mystery illnesses.
4. Osmoregulatory support, 0.5% (5 ppt): 5 g per liter (≈18.9 g per gallon).
5. 3% dip (slime strip / external parasites): 30 g per liter (≈113.6 g per gallon) in aerated, temperature-matched water. About 30 seconds for a crisis parasite strip; up to a few minutes for general parasites, watching continuously. Return the fish to clean water and expect an ammonia spike. Used for ich, costia, chilodonella, trichodina, flukes and gill rot, often followed by a multi-day treatment.
6. Not for pineconing dropsy: use a small Epsom salt dose instead, not table salt.
7. Top off evaporation with fresh water, not salted water. ppt is not ppm: 0.1% = 1 ppt = 1000 ppm.

Cautions (site): the 3% dip is ~3% by weight, not 3 ppm, and is a dip, not a bath to leave fish in. Stressed or ulcerated fish tolerate dips poorly. In ponds with chilodonella, hold a weighed therapeutic salinity from the table below — don't guess teaspoons as %.

1. Dropsy (pinecone) and floating protocols without NaCl: small dose, e.g. 1/8 tsp per 5 US gallons (= 1/8 tsp per ≈18.9 L; ≈ 1/40 tsp per gallon ≈ 0.0066 tsp per liter). Do not escalate blindly — more is not better.
2. Constipation / floating: Epsom-in-pea, carefully; or heat + Epsom without NaCl in a shallow recovery tub. Ammonia monitoring is mandatory.
3. Laxative bath (constipation): 30 g per liter (≈113.6 g per gallon) for 30 minutes, in a separate container.
4. Egg-bound bath: 1 g per liter (≈3.8 g per gallon) for 30 minutes, daily, in a separate container.
5. Not table salt. The in-tank dose above is by teaspoon only — no gram figure. Steps for the baths: Protocols.

1. Quick dip: 1 part 3% H₂O₂ to 9 parts tank water; dip 10–12 seconds. (≈100 ml H₂O₂ + 900 ml water makes 1 liter of dip; ≈379 ml H₂O₂ + ≈3.4 L water makes 1 gallon.)
2. 10-minute dip (protozoans and flukes): 15 ml 3% H₂O₂ per liter of water (≈57 ml per gallon); dip 10 minutes. Watch for distress.
3. Dosing during a water change: 2–4 ml per gallon (≈0.5–1.1 ml per liter) for 2 hours, then a 50% water change.
4. Fish-safe tank dose: 0.125 ml per gallon (≈0.033 ml per liter).
5. Deactivate potassium permanganate: 1.5 ml per gallon (≈0.40 ml per liter).
6. Wound cleaning: clean a wound once with dilute peroxide, carefully — keep it off eyes and gills.

Cautions (site): high risk — overdose, or longer/stronger dips than these, destroys gills. For flukes, praziquantel is preferred when possible.

1. Short bath: 10 ppm (10 mg per liter ≈ 38 mg per gallon) for 30 minutes, closely watched.
2. Longer bath: 2 ppm (2 mg per liter ≈ 7.6 mg per gallon), 4 hour minimum.
3. Whole-tank treatment: 4 ppm (4 mg per liter ≈ 15 mg per gallon) for 8 hours. Bypassing the bio-media in the filter is best practice but not strictly necessary. Run lots of surface agitation. Repeat once a week, 4 times; on the last round keep the bio-media in.
4. High-concentration dip: 100 ppm (100 mg per liter ≈ 379 mg per gallon) for 8–9 minutes. Every 4 days at 70°F or warmer; once a week at 64°F or cooler. High-risk dose.
5. Neutralize: 3% hydrogen peroxide, same volume as the PP dose.
6. Watch ammonia and nitrite: the treatment can kill off beneficial filter bacteria.
7. Never mix with formalin.

Cautions (site): strong oxidizer — use only if you understand organic demand, the color endpoint, and neutralization. Mixing with formalin is a fire/explosion risk. Dose from a concentrated stock solution diluted to the target ppm. The water should stay pink; if it clears instantly, organics ate the dose — don't blindly redose. Not on fried gills. Uses on the site: flukes (with salt dips) and external bacterial disease such as columnaris.

1. Waterborne treatment for bacteria, fungi and protozoa (Diseases of Carp, treatment table).
2. Harms the biofilter: damages the nitrifying bacteria, so it can't easily be used in a tank with a biofilter (Diseases of Carp).
3. Don't combine with oxidizers such as potassium permanganate or hydrogen peroxide.
4. Dose: per label.

1. Dose: per label. Multi-day courses (often ~3 days) with water changes between doses. Label example (Aquarium Solutions/Hikari Ich-X, malachite green chloride): 1 tsp (≈5 ml) per 10 US gal = 0.5 ml per gallon ≈ 0.13 ml per liter, giving ≈15 mg/L formalin and ≈0.05 mg/L malachite green (Hikari Ich-X data sheet). Overdoses can kill fish.
2. Uses (site): ich (target is the free-swimming stage; cycle length depends on temperature — days when warm, weeks when cold; some keepers add 3% salt dips while warming gently to ~72–74°F), velvet, costia and chilodonella (after a 3% salt dip), trichodina, flukes, and formalin-type products for epistylis. Part of the quarantine trio.
3. Cautions: toxic; lowers oxygen; light-sensitive; not for fried gills; local regulations apply. Never mix with PP.

1. Dose: 2 mg per liter (≈7.57 mg per US gallon) of veterinary or lab-grade praziquantel (Dr. Erik Johnson, drjohnson.com). Products such as PraziPro: per label. Stir the powder vigorously into a liter of clean water, then add it to a high-flow area. Turn off carbon and UV during treatment. For flukes, Dr. Johnson suggests one repeat dose 4–5 days after the first.

   Water volume	Praziquantel at 2 mg/L
   1 L	2 mg
   1 US gal (3.785 L)	≈7.6 mg
   10 US gal (37.85 L)	≈76 mg
   50 US gal (189.3 L)	≈379 mg
   100 US gal (378.5 L)	≈757 mg
   500 US gal (1,892.5 L)	≈3,785 mg (≈3.8 g)
   1,000 US gal (3,785 L)	≈7,570 mg (≈7.6 g)

2. Uses: flukes and some digeneans. Preferred over peroxide dips for flukes.
3. Skin flukes (Gyrodactylus): live-bearing; worse in warm water and poor conditions. Praziquantel at the dose above; light salt (weighed) supports slime.
4. Gill flukes (Dactylogyrus): egg layers — retreat and recheck over weeks (eggs hatch in ~4 days near 68–70°F). Bucket-to-bucket moves help leave eggs behind. Don't blast heat for bacteria until gill flukes are dealt with.
5. Mixing: the powder is hard to wet — mix thoroughly.
6. Also part of the quarantine trio (with metronidazole, as Fritz ParaCleanse).

1. Dose: per label. Complete the course.
2. Uses: Hexamita / hole-in-head style lesions and some protozoa. Medicated food preferred; water doses have also been used.
3. Also improve diet and water; reconsider carbon media if suspected as a contributor.
4. Also part of the quarantine trio (with praziquantel, as Fritz ParaCleanse).

1. Dose: per label; start with vetted guidance — dose confusion is common in hobby lore.
2. Uses: anchor worm (Lernaea) and fish lice (Argulus) in ponds, on a multi-week schedule, after manual removal and topical wound care.
3. Cautions: restricted; availability and legality vary; toxic to invertebrates.

1. Dose: per label.
2. An insect growth regulator (see above) for anchor worm and fish lice in ponds.
3. Cautions: may be unavailable, renamed or restricted. Prefer current labels and vet guidance.

1. Dose: per label.
2. Only with correct hardness/pH (site mention: black spot, digenean cysts).

Given to fish when you receive them, if you're worried about bringing disease into your fish room before adding new fish. Three products used together:

• Erythromycin (Fritz Maracyn) — bacterial infections.
• Formalin + malachite green chloride (Aquarium Solutions/Hikari Ich-X) — ich, other external parasites and fungus.
• Metronidazole + praziquantel (Fritz ParaCleanse) — internal parasites, gill flukes and some external parasites.

1. Dose (Aquarium Co-op's instructions — ignore the box directions for this combo): 1 packet Maracyn + 1 packet ParaCleanse + 1 US tsp (5 ml) Ich-X per 10 US gallons. Per gallon: 0.1 packet of each + 0.5 ml Ich-X. Per liter: 1 packet of each per ≈37.9 L + ≈0.13 ml Ich-X per liter.
2. Before dosing: keep the quarantine tank away from your other tanks, with its own nets, siphons and buckets; wash hands and arms with soap and hot water between tanks. Remove chemical filtration (such as activated carbon or Purigen) and turn off UV. Add extra surface agitation. Keep the filter and heater running.
3. Soak 7 days without feeding and without water changes (if you must feed, wait until day 4–5 and feed very lightly). Aquarium lighting will not deactivate the medication. After the week, change 30% of the water, resume feeding, keep the water quality high and watch for any change in symptoms.
4. Weak fish: give one med per week instead — Maracyn in week 1, Ich-X in week 2, ParaCleanse in week 3, each at the dose above.
5. If you can clearly identify the disease, use only the matching medication, per its label.
6. Ich-X at this dose gives ≈15 mg/L formalin and ≈0.05 mg/L malachite green (Hikari Ich-X data sheet).

Cautions: Fritz's ParaCleanse directions say it may inhibit nitrifying bacteria — watch ammonia and nitrite. An Ich-X overdose can kill fish. Ich-X contains formalin: never use the trio alongside potassium permanganate. Not on fried gills.

1. Humane euthanasia only: sedate with a few drops mixed in warm water, then overdose once movement stops. The site gives no measured per-liter dose.
2. Confirm death before disposal. Don't flush; dispose per local rules. Prefer vet guidance when possible.

Gear, empty tanks and nets only — never with fish present. Use plain, unscented bleach (no scent, no "splash-less" or cleaner additives) and check the % sodium hypochlorite on the bottle, since strengths vary.

1. Mix (club recipe): ½ US cup (≈118 ml) bleach per gallon of warm water = ≈31 ml per liter (about 2 tablespoons). For 5 gallons, 2½ cups (≈591 ml); for 10 gallons, 5 cups (≈1.18 L).
2. Contact time: soak or keep wet for 20 minutes.
3. Rinse well with clean water.
4. Dechlorinate: give everything a final rinse or soak in dechlorinated water. On tap water, your regular dechlorinator does the job.
5. Air dry completely, in the sun if you can.
6. Strength check: with 6% bleach this recipe is ≈1,900 mg/L (ppm) sodium hypochlorite; with 8.25% bleach it is ≈2,600 mg/L.
7. Sponges and filter media from a sick tank: replace them rather than trying to bleach them (club's notes).

Cautions: never mix bleach with ammonia or acids (vinegar, rust removers, toilet-bowl cleaners, ammonia-based glass cleaners) — toxic gas. Mix only with water. Wear gloves and work with good airflow. Chlorine kills fish and filter bacteria: rinse, dechlorinate and dry before anything goes back in a tank.

A powdered oxidizing disinfectant. Label actives: potassium peroxymonosulfate 21.41%, sodium chloride 1.50% (US label, EPA Reg. No. 39967-137). Use Virkon Aquatic only — not Virkon S (club's notes). Weigh it: small tanks need fractions of a gram, so use a scale that reads to 0.01 g. Koi sources use 5 g tablets and often UK gallons (1 UK gal = 4.546 L); figures below are converted to mg per liter and US gallons.

1. Gear, nets and tank surfaces (label): 1% solution = 10 g per liter (≈37.9 g per gallon; the label's 1 scoop ≈ 1.3 oz per gallon). Dissolve the powder in water first. Keep surfaces visibly wet for 10 minutes; soak gear that moves between tanks for 20–30 minutes, then rinse with water. Mixed solution keeps up to 7 days; change a foot dip every 2–3 days or when dirty.
2. No fish in the water (club's notes): 20 g per 1,000 L = 20 mg per liter (≈0.076 g per gallon).
3. With fish in the water — koi-keeper range:
   • Routine: 1–2 mg per liter (≈3.8–7.6 mg per gallon; the common "one 5 g tablet per 1,000 gallons" is ≈1.1–1.3 mg/L), once a week, with a 5–10% water change before each redose.
   • Quarantine or suspected virus: 2–5 mg per liter (≈7.6–18.9 mg per gallon), every 3 days or twice a week — up to daily for one week in a suspected virus outbreak — with at least 10% water change weekly.
   • Club figure: 5 mg per liter (0.0189 g per gallon) — inside the range, at the top end (the quarantine / suspected-virus level), not a routine dose.
   • Upper limit reported in the manufacturer's koi trials: no harm to koi up to 10–12 mg/L. Don't go there on purpose.
4. How to add it: dissolve in a bucket of tank water first, never drop powder or tablets straight in. Add slowly where the water circulates, pumps running. Turn UV off while dosing (UV breaks it down). Expect slight foaming if water changes are skipped — the fix is a lower dose and more water changes.

Cautions (label, SDS and koi sources): the US label says Virkon Aquatic must not be applied directly to water — it is registered as a surface and equipment disinfectant, so every water dose above is outside the label, and the koi guides themselves are issued "on an advisory basis only". It sanitizes the water; it does not treat sick fish, and it is not a bath or dip. It is bactericidal, so watch ammonia and nitrite. Oxidizers work less well in hard water, which is why some sources dose higher there. The current US safety data sheet lists sodium dodecylbenzenesulfonate (a surfactant) at 10–20%, the ingredient the club's notes warn about in Virkon S, so watch fish closely and stop at any sign of distress. The powder is corrosive: it causes irreversible eye damage and skin burns — wear goggles and waterproof gloves, and avoid breathing the dust (the diluted solution is not corrosive). Don't soak metal for long; take metal out within an hour. Mix only with water; store dry, cool and tightly closed. Toxic to invertebrates such as shrimp and daphnia. Don't drain used solution into ponds, streams or storm drains.