Hi Lary
my only concern is the older fry attacking the newborns
Don't worry. 
I deliberately place very young fry together with older fry. The older fry don't attack them or something like that. 
Instead - the older fry know how and where to search for food -and the younger ones just follows.
I would even recommend to do this. 
Of course - when the older "fry" gets to big - they should have another tank. 
Topic "bulldog fry" 
Quite a long and exausting thread. I gave up - read the beginning and the end.  
I probably missed something in the middle *smile* - I'm wondering if anybody at all thought about bacteria growth infecting on the fry?
In the very beginning I used plastic containers in the tanks. Everything worked all right. Why replace them with glas then?
The plastic containers got older - and naturally more scratched and destroyed. A perfect "substrate" for bad bacteria growth.
Suddenly I had spawns with nearly 100 % with absolutely destroyed fins (L134), death and problems all along. Nothing helped at all. 
I started placing the new fry in their own little tank with sand. Directly from spawning tank and directly from the cave. 
Since then I had 100 % healthy youngsters. 
I never used containers since then. If so, I strongly advice to use glas ones. 
We have just heard TwoTankAmin and Barbie - none of them use the containers and none of them have bulldog fry. 
My experiment: all from wildcaught parent and from another breeder: 
I have bought/ adopted most of all their spawns till now. 
This breeder had bad luck and a lot of bulldog fry. I adopted these too. 
That means, I have them all and eventually brothers/sisters - some bulldog - some healthy. The bulldog ones could naturally belong to the same spawn. The originally gene pool is big with a lot of different parents.
The healthy ones for sure bring normal fry. 
18 bulldog fry/youngsters are still growing out - having their own tank. IF these ones bring normal fry as well, I would claim that bulldog fry are caused from environmental defects. 
Or should I rather ask: when is it really proved? Should I crossbreed the hopefully healthy kids with their bulldog parents? If still normal - is it then proved? That would be in around 20-24 months. Please be patient  
 
 
And please notice: I'm not crazy about the bulldogs - they are indeed not beautifull. And nobody should sell them 
at all. No bulldog fry will ever leave my tanks! I simply just want to prove this matter. 
Best regards
Line