Treatment protocols & salinity

Unit caution: Do not mix up ppm (parts per million) and ppt (parts per thousand). 1 ppt = 1000 ppm. A target of 0.1% salinity is 1 ppt (= 1000 ppm), not 0.1 ppm.

Salinity table · Supportive care · Salt dip · Wounds · Bucket rotation · Heat notes · Potassium permanganate · Med notes · Euthanasia

Salinity & unit cheat sheet (US gallons)

Prefer grams. Use a kitchen scale. Teaspoon column is approximate only (crystal size varies).

• 1 US gallon freshwater ≈ 3785 g
• % = percent by weight; % × 10 = ppt; ppt × 1000 = ppm; g salt / gal ≈ 37.85 × %
• Teaspoon column assumes 5.0 g salt per level teaspoon — last resort if you have no scale

If you measure by teaspoon instead (last resort)

At denser crystals (~5.5–5.7 g/tsp), 1 tsp/gal lands closer to ~0.145–0.15% (~1.45–1.5 ppt).

Contradiction flag (important)

Some hobby texts say things like .1% ~1 tsp/gal and .3% ~3 tsp/gal. That overshoots true percent-by-weight. Use this table, not the tsp shortcuts.

Quick check before you dose

1. Decide target in % or ppt (0.1% = 1 ppt).
2. Convert to grams per gallon (preferred — weigh it).
3. Only then approximate teaspoons if you lack a scale.
4. Never read ppt as ppm (off by 1000×) or % as ppm.
5. Watch salt creep: top off evaporation with freshwater, not salted water.

Common targets (context only)

• ~0.1% (1 ppt): light supportive salinity used in many goldfish hospital notes and example antimicrobial + salt courses.
• ~0.3% (3 ppt): stronger “therapeutic” range used for some mystery illnesses — species-dependent; not for dropsy pinecone protocols that ban NaCl.
• ~0.5% (5 ppt): “osmoregulatory support” level (~18–19 g/gal) — verify species tolerance.
• 3% dip (~30 ppt): short external salt dip (see below) — not a bath you leave fish in.

Supportive care (do this often)

• Match temp and pH on water changes; dechlorinate.
• Heavy aeration whenever treating or heating.
• Bare hospital tub: daily water changes, siphon waste, no décor that hides eggs/parasites.
• Feed sinking / soaked food; don’t starve sick fish for long if they will eat (immune fuel) — exception: short diagnostic fasts for uncomplicated floaters.
• Medicated food often beats water antibiotics for internal bacteria.

3% salt dip (slime strip / external parasites)

1. Mix ~30 g salt per liter (~113 g per US gallon) of aerated, temperature-matched water — that is ~3% by weight, not 3 ppm. Weigh it.
2. Dip fish briefly (often ~30 seconds for a crisis dropsy parasite strip; longer dips up to a few minutes are used for general parasites — watch the fish continuously).
3. Return to clean aerated hospital water. Expect purge and ammonia spike — change water.
4. Not a cure-all; follow with appropriate multi-day treatment if parasites remain.

Caution: Stressed, ulcerated, or scaleless fish tolerate dips poorly. Some koi lines are described as salt-intolerant.

Wound / ulcer protocol (parasites first)

1. Parasites first — salt dip or labeled antiparasitic so heat/bacteria treatment doesn’t explode flukes/costia.
2. Clean wound once with dilute peroxide carefully — keep off eyes and gills.
3. Topical: antibiotic cream rubbed in well, 1–2× daily (prescription topicals via vet when needed).
4. Bacteria support: antibiotic food; hospital warmth only after parasites addressed; optional vet injectables.
5. Move to fresh aged water daily so fish leave shed pathogens behind.
6. Do not squeeze lumps/boils.

Bucket-to-bucket / hospital rotation

Used for egg-laying parasites, lice/anchor-worm egg escape, dropsy courses, and wound cases:

• Two (or more) tubs; big airstone; heater secured so fish cannot lie on it.
• Move fish daily to fresh matched water; bleach/clean the empty tub and stones; dechlorinate and age overnight.
• Feed before moving so leftovers stay behind.
• Minimum often ~10 days (arthropod eggs) to ~2–4 weeks (dropsy hold).

Heat protocols — use with eyes open

• Hospital temps for bacterial/dropsy cases are commonly 84–86°F with max aeration.
• Raise ≤ ~2°F per hour from cool pond temps; parasites must be handled first.
• Hold long enough (days to see scales settle; weeks before cooling) — early cooldown → relapse.
• Cool slowly (~2°F/day) back to display temp.
• For dropsy: no NaCl; small Epsom only (example: 1/8 tsp per 5 gallons — do not “more is better”).
• Species note: these heat and salt levels are for goldfish; other species need their own.

Potassium permanganate (hazardous)

Strong oxidizer. Use only if you understand organics demand, color endpoint, and neutralization. Never mix with formalin (fire/explosion risk).

Stock/dose method (verify independently before use):

• Stock concept: concentrated PP solution diluted to target ppm in the tank.
• Example baths: ~2 ppm longer bath; ~10 ppm ~30 minutes closely watched.
• Neutralize with 3% hydrogen peroxide (know your method).
• Water should stay pink; if it clears instantly, organics ate the dose — dangerous to “blindly redose.”

Prefer milder labeled products unless experienced.

Medication notes (verify labels / laws)

Example course tone (not a universal Rx): daily large water changes; labeled antimicrobial per bottle; hold salinity at 0.1% (1 ppt) using the gram table; stop on schedule unless symptoms persist. See also Protocols.

Humane euthanasia (last resort)

Clove-oil method: sedate with a few drops mixed in warm water, then overdose when movement stops; do not flush; dispose per local rules. Prefer vet guidance when possible. Confirm death before disposal.

Goldfish temperature / feeding reminder

• ≤50°F: stop feeding
• 50–60°F: every 1–2 days, lower protein
• 60–85°F: 2–4×/day higher protein
• ≥85°F: stop feeding (metabolic/O₂ stress)