Hi,
Your discus does not look well. The color is off and its definitely not growing well. It could be because its a runt genetically unable to grow or because its growth has been stunted by something like disease or sub optimal care.
I would suggest copying and pasting this questionaire..
https://forum.simplydiscus.com/showt...lease-complete
To this thread and filling it out so we get a better idea of the situation.
Also.. can you post pics of the other fish too.
Thank you,
Al
Ps..Welcome to SimplyDiscus!