vanishing Brichardi fry

Were the parents the only fish in the tank other than the newborn fry?

What is your water change schedule and how much do you change? Do you have a nitrate test kit, and if so what are your nitrates? From your other posts, you have a few older batches of fry in there, right? How do they look (skinny, fat, torn fins, losses)? How big were the fry that dissapeared?

Young fry will be more sensitive to changes in water quality than older fish. And it's pretty hard to underfeed in captivity: food in the wild isn't easy to come by so that isn't my first guess. If water quality is good, and no obvious predators (any catfish in the tank?), then this trick may help: Crushed flake that's been stirred into a glass of tank water can be poured into the tank to disperse the food more quickly and evenly. If starvation is an issue, then feeding more to the tank isn't going to help as much as getting food to where the fry are. A turkey baster or pipette work as well.

Brichardi don't eat their babies,so I know its not that.I usually do 50% every 3 weeks. I have been keeping an eye on the ammonia, nitrates and nitrites and they are all 0 except for nitrItes which is 5ppm. Everyone else seems healthy,but I think I am going to do a water change today.Thanks.

I do not think its a food issue. Even fry do not need much to survive. Fast growth is another thing to survival, I have had em survive despite adding no food for the fry.
Good luck. Look toward water quality and group dynamics and possible predation I think.
Males will kill other males fry given half a chance.
New dominant breeding females have attacked other females fry too.
But once they start I reckon just keep it nice and clean and you will soon be swamped with young whatever the breeding type strategies the fish finally settle on. :thumb:

Do 30% water change each week rather than 50% every 3 would be better I think. 8)

Though that depends on the size of your group.
How many is it?

The parent won't eat it's OWN babies, but other adults will eat fry not their own, right? My understanding of Brichardi dynamics is the breeding pair kill all the other adults, and then they protect their own fry.

If you really have nitrites of 5ppm then I would say that is the reason. My adult fish start to freak out of nitrites get to 0.5 ppm. Did you mean nitrates maybe?

Nitrates for an established tank even with weekly 50% water changes tend to hover around 10-20 ppm. Check your test kit and if it's the drop kind, follow the instructions very closely. I thought I had no nitrates when I started testing because I didn't shake my bottles and test tube enough.

If you have ANY nitrite or ammonia, then you've got problems.

OK, changed water in both tanks, vacumed the 55 changed filters and will test the water in one hour. Fingers crossed( I only see 1 fry left)

Young parents, and some parents with poor skills have been known to eat their fry. If they are new at this, give them a few chances, and eliminate other possibilities that have been listed in this thread. N. brichardi normally become excellent parents, but there are exceptions to nearly every generalization (except this one!!).

i do agree with fogel.
even older parents sometimes eat their fry.
mine were around 3-4inches and they are their first spawn. but it didt happen again