help! albino longfin bn fry keep dying...

[Prive]

hi guys, my problem is that i hatch my albino longfin bn fry, but when they get between 6-8weeks old, they start dying on me. for the last 3batches, ive had about 50 fry hatch and only about 5-10fry survive to about 3-4cm.
ive tried leaving a batch in a fry saver, not changing water for the 1st 8weeks and keeping them with their dad and letting them swim freely in the tank. nothing is working for me. they seem to eat nicely until they reach 6-8weeks of age.
My shortfin albino bns are fine. i leave them with their dad and most of the fry survive. its just not the case with my longfins.

any suggestions on how i can make more of them survive?

 

[Doodles]

8 weeks is a long time to go without changing any water.
Do you know the TDS of both the long fin and short fin tanks?
Also what temp are you keeping them at?
What substrate do you have?

 

[Breamlegend]

Try a uv filter. I had the same problem with pepp fry. Never had a problem again after using a uv filter. I change water weekly. What are your nitrate readings?

 

[Irene0100]

When I have a lot of young I change the water almost daily.
how big is thetank? is there enough filtration and oxygen?

 

[Breamlegend]

Try increasing your filtration. You cant have too much imo. eg. My 4 foot standard has an eheim 2215 with a fluval 305. Two large sponge filters and an internal. lol. A 3foot with 2x 2215's and two large sponge filters and an internal.

 

[GrubbyGirl]

I would guess not changing water for 8 weeks is your problem. I would be doing more frequent rather than less frequesnt water changes. Even fry produce a lot of poop!