Fry Loss??

Hi Guys,
what would you expect to be natural fry loss?
I ask because i have a 350ltr tank (280ltr of water) with community fish.
I have endlers in here and my tank is now full of fry approx 80.
In the last 2 days i have found 2 dead fry.
They had a milky appearance but this may be because they are dead??
I am in the process of selling my female endlers as they are like machines at producing fry and i am being over-run.
The tank mates are 3 platy's, 4 dalmatian mollies, 2 neons, 4 gold cloud mountain minnows, a common BNS pleco and a golden sucking loach (juvenile), this is in addition to the 4 females and 3 male endlers.
Checked water and i have 0 nitrites, nitrates and ammonia.
Started water changing with RO water to bring my TDS down ready for some pleco's. This hasn't affected the water parameters tooo much so far as i am changing 70 litres of water (30%) and of this 50 litres is RO with 20 litres treated tap water.

Would you say this was just natural loss as the rest of the fish appear absolutely fine.

I also have a bubble curtain so i don't suppose it could be lack of oxygen in the water as i have plenty of surface disturbance.

seems normal to me

I woul keep a close eye on everything just to be sure. I know with swordtails I get the occasional individuals that just won't grow right. Their siblings will be 2-4x bigger than them and they eventually die.

I am too inexperienced with BNs to say the same for them though. My pair successfully hatched 6 witch are all doing fine (counting my blessings!)