Carp pituitary vs HCG: what hatcheries actually use, and why
Every year someone tells a hatchery manager that HCG is cheaper and easier. It is, for one season. Here is the honest comparison — including the cases where HCG is the right answer.
I sell pituitary gland, so weigh this accordingly. But I also lose customers to HCG every season and get some of them back the following year, and the pattern of who comes back tells you most of what you need to know.
Two different mechanisms
HCG is a single hormone: human chorionic gonadotropin, one signal aimed at the ovary. Dried carp pituitary is the whole gland — GTH plus the supporting factors the carp's own pituitary releases during final maturation. The fish's reproductive axis evolved to respond to the whole signal, not one note of it.
In practice this shows up as a difference in how the ovulation window behaves. With hypophysation, the latency window is wide and forgiving; you can be an hour late and still strip clean eggs. With HCG alone the window is tighter and the share of overripe or watery eggs is higher, especially in first-time spawners.
Side by side
| Factor | Dried carp pituitary | HCG |
|---|---|---|
| Active principle | Full gland complex (GTH + cofactors) | Single hormone (hCG) |
| Typical dose, female | 2–5 mg/kg, two injections | 500–1000 IU/kg |
| Response in first-time spawners | Consistent | Variable |
| Ovulation window | Wide, forgiving | Tighter |
| Egg quality at stripping | Stable between batches | More overripe / watery eggs reported |
| Repeat seasons on the same broodfish | No desensitization issue (heterologous but gland-based) | Effectiveness tends to drop in reused schemes |
| Storage | 2 years sealed, ambient, dry | Cold chain per label |
| Price per female treated | Higher on paper, stable | Lower on paper |
The cost that matters is per egg, not per vial
The HCG quote is always lower. But the comparison that decides the season is cost per viable fry, and that number includes the females that got injected and produced nothing. One failed night on 100 females costs more than the entire hormone budget for the year, whichever product you use. Hatcheries that switch to HCG and keep good records usually discover the "savings" were smaller than the losses on failed sets.
Who does well on HCG anyway
Small farms treating a few dozen fish, operations where the veterinary rules make gland import difficult, and species where pituitary dosing has never been worked out. If your spawning window is flexible and a 60% take rate is survivable, HCG is a reasonable tool. Not every farm needs gland extracts, and I tell buyers that.
The scheme big hatcheries actually run
The most experienced operations don't pick one. A common pattern: a small priming dose of pituitary to start final maturation, then HCG or a larger pituitary dose as the resolving injection. The gland priming dose does the groundwork the single hormone can't, and the total cost stays close to an HCG-only scheme. Ask around at any serious carp farm — you'll find some version of this everywhere.
Three rules that survive every season
- Record what your fish did, not what the label promised. Broodfish respond to your water, your temperature, your handling. Local records beat every comparison table, including this one.
- Don't switch products mid-season. Whatever you choose, run the whole season on it. Changing protocol in April means you'll never know what caused the May failure.
- Dose by weight, not by fish. This failure mode is identical for both products and it is the most common one.
Planning this season's protocol?
Tell me your broodfish count and water temperature range in WhatsApp. I'll send a dose plan and a door-to-door price with the batch COA.
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