I'll bet they didn't survive because of the pleco, plecos are notorious egg, and wriggler eaters, and they tend to do their snacking at night when cichlid parents are sleeping, and you wouldn't notice.
And if the cichlid parents know there is a fry predator near, they will often eat the eggs and/or fry themselves, rather than let a pleco or anything else get them.
thankYou, and interesting to know..
also I found my gt parents defend to the death basically, but the jd and gjd, abandon quickly,like she'll not move from there but when I was cleaning the glass, didn't go for me going for the glass, like the gt pair would, she ran away after just a few seconds,not trying to defend or anything. the jd was up other end of tank, she seems to have 'kicked him out'
but they really aren't good parents,none of their fry survives like the gt pairs fry, and I have 9bn and1 common plec in the tank where the gt pair are, but find over time the fry just gradually disappear,prob down to what you said,with the pleco at night etc, but the jd's, just seem to leave them and the fry disappears quicker than what my gt pairs fry did, so they aren't good in that sense