🙂 perhaps he didnt count the weeks before he actually saw them :blink:
But some fry do grow rather quick, – I know that sometimes it seems to take ages, but some species I would say 3 months is enough to reach the size your fish has. They look grown up, adult yet probably smaller in size. But possible to sex them though.
They look fine and healthy, – interesting fish.
You can see a thread about the development of fry here https://www.parosphromenus-project.org/en/forum/17-Pictures/1563-close-up-of-fry.html?start=12 – note the last photo of a male app. 4 months old.