Vet AI Scribe for Aquatic

Kintaro

Saturday, June 14, 2025 at 9:05 AM

Subjective

Chief Complaint

Owner reports a 10-day history of a progressively enlarging red ulcer on the left flank of an adult koi, with flashing against the pond liner and reduced interest in food.

History

• 1,800-gallon outdoor pond; eight koi and four goldfish, stocked five years.
• Two koi added six weeks ago from an outdoor retail pond; no quarantine performed.
• Partial water change (~15%) weekly; last change four days ago.
• Biological filter media rinsed with chlorinated tap water three weeks ago.
• Fed floating pellet twice daily; intake down roughly half since signs began.
• No mortalities to date; one other fish observed flashing intermittently.

Objective

Water Quality (owner sample, tested in clinic)

• Temperature: 71°F
• pH: 8.4
• Ammonia: 0.5 mg/L
• Nitrite: 0.25 mg/L
• Nitrate: 10 mg/L
• Carbonate hardness (KH): 60 mg/L
• Salinity: 0 ppt

Physical Exam (sedated, buffered MS-222 at 75 mg/L)

• Weight: 1.4 kg Length: 38 cm
• Skin: 2.5 cm round ulcer on the left flank caudal to the pectoral fin; raised erythematous margin, central scale loss, exposed dermis
• Fins: Mild fraying of the caudal fin margin; no haemorrhage
• Gills: Pale pink, moderate excess mucus, no gross parasites
• Eyes: Clear bilaterally; no exophthalmos
• Coelom: Soft, no distension
• Vent: Clean; no prolapse or discharge

In-House Diagnostics

• Skin scrape, ulcer margin: Moderate numbers of Trichodina sp.
• Gill biopsy: Low numbers of Trichodina sp.; mild epithelial hyperplasia
• Mucus wet mount: No monogeneans seen

Assessment

Primary Problem List

1. Ulcerative dermatitis, left flank — secondary bacterial infection suspected
2. Trichodiniasis — skin and gill
3. Nitrogenous waste elevation — ammonia and nitrite both detectable
4. Biosecurity failure — unquarantined additions six weeks prior

Differentials

• Aeromonas hydrophila or atypical A. salmonicida ulcer disease
• Koi herpesvirus — unlikely without mortality or gill necrosis, but not excluded
• Trauma with secondary infection
• Spring viraemia of carp — reportable, but at 71°F the pond is above the range in which outbreaks occur; retained on the list only because two fish entered unquarantined

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Plan

Diagnostics

• Bacterial culture and sensitivity from the ulcer margin, deep swab taken after debridement
• Daily water testing until ammonia and nitrite read zero
• Gill PCR panel for KHV and SVC if any further fish declines or dies

Treatment / Management

• Wound care: Ulcer debrided under sedation; topical silver sulfadiazine applied and sealed with a thin layer of medical-grade cyanoacrylate
• Antimicrobial: Enrofloxacin 5 mg/kg IM q48h for five treatments, pending culture
• Salt: Raise pond to 0.3% (3 g/L) over 24 hours to reduce osmotic load and address Trichodina
• Water: 25% change today, then 15% daily until ammonia and nitrite are undetectable; stop rinsing filter media in chlorinated water
• Feeding: Reduce to once daily at 1% body weight while nitrogenous waste is elevated
• Biosecurity: Establish a quarantine tank; 30-day quarantine for all future additions

Follow-Up

• Recheck ulcer and repeat skin scrape in 7 days
• Culture reviewed at 48-72 hours; antimicrobial adjusted if indicated
• Owner to log daily water parameters for review at recheck

Client Communication:
Discussed the link between rinsing the biofilter in chlorinated tap water, the resulting ammonia and nitrite rise, and the fish's reduced ability to resist opportunistic infection. Reviewed the salt dose calculation for this pond volume and demonstrated adding it gradually rather than all at once. Quarantine protocol handout provided. Owner advised that spring viraemia of carp is a reportable disease and that samples will be submitted if additional fish decline.

— Dr. Priya Raman, DVM