Please help ! Goldfish fry

[Ellabrathwaite]

Hello,
My fish layed eggs on the 10th September and currently there is only one fry left as the others have died.
It seemed really healthy and has been doing great, however comparing it to pictures of the internet he has not grown as quickly as others and seems to have not grown fins on its tail yet.
I feed it egg yolk about 3 times a day.
Help would be much appreciated as I want to do anything I can to keep it.
Also it seems to be a lot less inactive than it was before.

 

[Arleanna]

Id invest in some first bites fry foos or at least start crumpling in flake food if it's large enough.
Live food like infusoria (

) or brine shrimp would be ideal, but i think your fish isn't getting enough nutrition from just that egg!