Mom went mad

[caue]

Hi Guys,

I am a first time breeder. Just going to give a brief history of my case here:
I have a main tank where I use to have only 3 Discus. For my surprise 2 of them formed a pair and started to laying eggs every week on the tank. Off course they would eat them all after starting free swimming as they were with other fishes in the tank.
I finally create the courage (and money) to buy them a breeding tank (123 liters) and set it up with only a cone. They attempted several times but every time the fry started free swimming they would not attached to the parents. I realized that this tank was quite big, even lowering the water level and doing every tip I could find they would not attach. This last time I moved the parents with the fry to a really small hospital tank that I have (20 liters) and the fry finally attached to the mother.
Everything was doing fine for about 2 weeks, they were growing and already eating BBS. I've notice though that only the mother would keep the fry all the time. The dad would try to get them but with no success. They would swim straight back to mom. This last day the parents start fighting. Maybe for the custody of the kids? But was not anything really violent, so I just left.
For my surprise yesterday when I came to feed them Mom was trying to eat them all and dad was trying to protect the fry like crazy. I put Mom back to the breeding tank and left them with dad. Unfortunately only 12 babies survived what was really frustrating (was more then 50 before). I've also noticed that those left were not attaching to dad so I took him out as well as they are already feeding by themselves.

Tank water is set at 29 degrees Celcius and PH is 6.6. I was doing daily water changes of about 80% with mature water from the breeding tank. Feeding BBS 3x and parents 2x a day.

As first time breeder every thing is a learning process for me, so I would like your guys opinion in what could have happened so I won't make the same mistake again.

Apologies for any English mistake but English is not my first language.

Cheers

[pastry]

Carlos, I don't think you did anything wrong. Great job! BUT, since it sounds like the next try or 2 you'll have a good number survive (since you know to take mom out once free swimming), then you might need to be ready to get a few grow out tanks

[caue]

Carlos, I don't think you did anything wrong. Great job! BUT, since it sounds like the next try or 2 you'll have a good number survive (since you know to take mom out once free swimming), then you might need to be ready to get a few grow out tanks

Thank you.

I wonder if they were annoyed to be in the small tank still. Should I have moved them to the bigger tank when they fry attached? I was worried to be hard to feed the fry with the BBS in such a big tank...