[Peter Finke]

That’s an interesting topic and there is much information on it. But I do not know a place where it is gathered in a comprehensive way.
All experts agree that the development of young Parosphromenusneeds more time than with many other fish. Less than half a year until reaching the adult stadium is never experienced. I know of licorice gouramis bred by commercial breeders (who normally don’t breed these fish at all) that were only seven months and quite big and ready for spawning, but they were fed very intensively by Tubifex and in many cases didn’t live long later on. Many experts speak of (and experience themselves) three quarters of a year as the least. The pioneer Dr. Walther Foersch wrote of an interval of four or more weeks in the middle of the growing phase. In my opinion this depends on the circumstances; good, but diversified feeding and frequent water-change shortens the time they need for growing and may even let fall away that interval.
Therefore the time-span that Beutho tells us is to be seen as quite normal. That’s much compared with many other fish. But it does not indicate wrong treatment or false aquarist methods.
On the other hand, the fish we receive via the trade are mostly young fish of the last spawning period. Often, they arrive not yet in the adult stadium but still need two to four months in good care. That might indicate a somewhat faster development in nature. But I am not sure. The young fish of this year are the parent fish of next year’s spawning period. Therefore, a big difference to our aquarium observations is not to be seen. But we observe another thing, too: Some individuals of the same spawn grow faster, others less fast. This is a natural adaption, nature’s precaution against fate.
In general one can say: Parosphromenus are slow growers.