just to add, ive also been told that they hold the eggs for around 21 days. I've had mine release the eggs at 21 days before and none made it through the night.

Then one time he decided to hold on for what seemed like another week, this time i had about 15-20 little guys just happily swimming in my tank and a little shoal and nobody bothered them. (i knew someone who was breeding them so i gave them away).

good luck on raising your little guy, Ive succesfully raised 1 baby cardinal to adulthood, its great fun seeing them grow. and yeah, around the 1-2 week mark there is period where little ones die for what seems like no reason, nothing anybody can really do about it.