API General Cure Review Guide: Metronidazole and Praziquantel
API General Cure is one of those products that earns its place by doing two jobs adequately rather than one job brilliantly. This API General Cure review guide breaks down the metronidazole-praziquantel combination, where it genuinely works in Singapore community tanks, and where more targeted products outperform it. The notes here come from our bench at Gensou Aquascaping in 5 Everton Park, tested across dozens of import quarantines, hexamita outbreaks in angelfish and stubborn gill fluke cases that the LFS “treatment” never actually cured.
The Combination Approach
Each API General Cure packet contains 250 mg metronidazole and 75 mg praziquantel in a soluble powder. Metronidazole targets internal anaerobic protozoans like Hexamita, Spironucleus and Giardia, while praziquantel handles monogenean flukes and tapeworms. The two actives are complementary, covering the two most common import parasite categories in a single dose.
When It Is the Right Tool
Reach for General Cure when the symptoms point to internal parasites — stringy white faeces, head-hole pitting in cichlids, wasting despite good appetite, or the classic flashing with clamped fins that suggests flukes. For single-target problems, the dedicated products are better: pure praziquantel for confirmed flukes only, or metronidazole alone for confirmed hexamita. The combo shines in undiagnosed imports where you want broad coverage.
Dosing Freshwater Tanks
Label dose is one packet per 38 litres (10 US gallons) with a repeat dose at 48 hours. Run the full five-day course with a 25 percent water change before redosing on day three. In soft Singapore PUB tap, the powder dissolves cleanly in 100 ml of warm tank water — drip the suspension into high-flow near the filter intake rather than dumping it over substrate where it clumps and lingers.
Quarantine Protocol Integration
Most Singapore keepers now run General Cure prophylactically on all freshwater imports from Iwarna, C328 and Polyart. Set up a bare 40 to 60 litre quarantine tub per our freshwater quarantine setup guide with a cycled sponge filter. Dose General Cure on day 1 and day 4, observe until day 14, then return the fish to the display. Skip carbon entirely during the treatment window or you will strip the drugs within hours.
Marine Compatibility
General Cure is labelled for freshwater and marine use, though the marine dosing is less intuitive. Use the same 250 mg metronidazole per 38 litres but watch for skimmer foam — metronidazole is surfactant-active and can trigger skimmer overflow within an hour of dosing. Turn skimmers off for 12 hours post-dose. For reef tanks with corals and inverts, dose at half strength initially to verify coral tolerance.
Plant and Shrimp Safety
Both actives are plant-safe at label dose — crypts, stems and carpets tolerate the full course without visible impact. Shrimp are more sensitive: Neocaridina usually survive full dose but Caridina and Sulawesi species show stress. Our plant-safe medication guide details tolerance by species. Snails are essentially unaffected by either active at therapeutic levels.
Filtration and Cycle Impact
Metronidazole is relatively gentle on the nitrogen cycle, but the combo does perturb the biofilter enough to warrant daily ammonia and nitrite testing across the five-day course. Keep a bottle of Prime or equivalent on hand to bind any transient spike. Remove activated carbon and Purigen before dosing and only reintroduce on day 6 after the full treatment wraps.
Where It Falls Short
General Cure is ineffective against Ich, velvet, bacterial ulcers, columnaris and fungal infections. It will not touch external protozoans beyond mild Chilodonella. Using it as a first response to skin lesions or cotton-wool patches is a misdiagnosis that wastes five days while the real pathogen advances. Always match the medication to the pathogen via our parasite identification guide.
Singapore Sourcing and Shelf Life
A 10-packet box runs $22 to $32 at Iwarna, Polyart, C328 and Thomson shops. Shopee listings from authorised API sellers occasionally dip to $18 with free shipping. Sachets store well in a cool dry cupboard for three years — avoid humid bathroom storage, because the powder clumps and loses potency with SP Group humidity swings during wet season. Check expiry dates carefully when buying from smaller shops with slow stock turnover.
Verdict
API General Cure is a sensible default for undiagnosed import parasites and a staple in any serious Singapore quarantine kit. It is not a miracle broad-spectrum cure, and pairing it with proper diagnosis and hospital tank hygiene matters more than any single medication choice. Keep a box on the shelf, treat it as a targeted internal-parasite tool rather than a first-response universal, and it will earn its place across years of tank runs.
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emilynakatani
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