1 year ago, baby Cory was born

[TTboy79]

Last year in a newly set up 70lt I introduced a 4 C. juli (?) and after some time I started noticing a very little catfish hiding under a log, he grew up (see pic).
He was super cute!

Unfortunately the cory family Lasted not even a year, while other fish like Betta, minnows (ok, they’re super hardy) were fine and stil are.

How come they passed from reproducing to dying without any change in the environment?

 

[Naughts]

Cories do best in a group of 6+ on a substrate of soft sand. Substrates that are sharp, or large enough to trap particles, harbour bacteria that infect a cories mouth and barbles.
Incorrect parameters (temperature, GH, pH) or deteriorating conditions (ammonia, nitrite, nitrate) will also weaken them.
Your Cory was a c.trilineatus.