Orfe and Goldfish Deaths After New Additions: Disease, Medication, or Water Quality?

Multiple fish deaths after adding new fish and treating with Medifin—this is a classic "new tank syndrome" compounded by medication sensitivity and possible disease introduction. Here's how to untangle it.

Timeline Analysis

• New shubunkin and comet added → 2 dead within days.
• Surviving comet shows white fuzzy growth (likely fungus/Saprolegnia).
• Pond treated with TetraPond MediFin (malachite green + formalin).
• Golden orfe (5 years old) now listing, rolling, barely responsive.

Key Suspects

1. New fish introduced disease: Fungus, parasites, or bacteria from unquarantined additions.
2. Medifin toxicity to orfe: Orfe are notoriously sensitive to formalin and malachite green. The treatment may be harming them.
3. Water quality crash: Dead fish + medication + warm water = ammonia spike + oxygen drop.
4. Pre-existing orfe issue: Bent tail suggests old injury or genetic defect; stress may have triggered decline.

Immediate Actions

1. Test water: Ammonia, nitrite, pH, oxygen, temperature. This is non-negotiable.
2. Partial water change (30%): With dechlorinator. Removes medication residuals and toxins.
3. Add fresh activated carbon in mesh bag to filter to adsorb remaining medication.
4. Maximize aeration: Air pump + stones, waterfall at full flow.
5. Stop Medifin if orfe are worsening. Orfe often die from the cure, not the disease.

Safer Treatment Alternatives

• Pond salt 0.05%: Antifungal, antiparasitic, supports slime coat. Safe for orfe, plants, filter.
• MelaFix (tea tree oil): Natural antibacterial, gentle.
• If fungus confirmed: Treat at half dose of MediFin, monitor orfe closely. Or use salt + MelaFix only.

Quarantine Lesson

All new fish need 3–4 weeks quarantine. A simple 50-gallon tub with filter, heater, and cover prevents 90% of these disasters.

When to Accept Losses

If orfe continues declining despite clean water, salt, and aeration, humane euthanasia (clove oil) may be kindest. Focus on saving the remaining fish.

Pond ecosystems often self-correct once stressors are removed. Clean water, no harsh meds, and time are your best allies now.