Size Of Corys If Kept A Long Time

I was visting another fishkeeper to pick up a fish and see his fish room set up.

The person kept; a few L Numbers, different bristlenose catfish and varying sized fry, and also some quite large groups of corys, and varying sized fry.

What caught my attention was the size of some of the adult corys, i thought they were bronchis at first mixed in with the group, but the person just said they were his oldest corys and the smaller ones were just younger.

I've had cory groups for two or three years but they never reached that size and i thought mine were adult, i think the larger corys were nearly ten years old.
A group of Sterbai, were one of the species that he had the biggest ones i had ever seen.

Has anybody else kept corys for a long time and noticed this ?

Do you know what his water change regime was?

could they have been haroldshultzi?

The group were all Sterbai, and he also had a few other groups of different corys with the biggest adults i have seen, just can't remember there names, though the were common species of corys.

I don't think it was his water change regime, from what he said, it sounded pretty standard, weekly water changes.

I should have said earlier, he has kept fish for twenty to thirty years, and his dad was an avid fishkeeper, and he has a few of his fathers fish now, with his father not being able to keep as many tanks as he used to.

Maybe his largest corys are ones are just really old corys, that have been well looked after through the years, and don't breed anymore, but still pig out.

My sterbys are maybe 3 or 4 years old, a nice size. I remember seeing 'adults' at my LFS that were a good double the size of my fish, proper monsters lol. not seen any that big in a few years though, imagine the spawn size!!

some corys stay small, like pandas etc others grow bigger I think.