Little platy looks like he's struggling, advice would be appreciated

I have a 200 liter tank with a fancy oranda, two hill stream loaches, pearl and giant danios and 5 platys.

Speckle (little orange guy in photo) was the smallest of the bunch from the get go but while the others have grown in size, he seems to be getting thinner and rattier.

I noted a few weeks ago he seems to swim with a bent back. I had a danios with the same issue which has to be euthanized since he could no longer move or eat but Speckle still seems absolutely fine, just a little wonky. I decided to leave him to it and keep an eye on him.

Looking at him today, he seems thin. I worry he's struggling to contend with the others in the large tank and wonder if a much smaller tank with only a few platy tank mates might improve him.

I don't want to jump the gun and euthanize him since up until this point, I really haven't had any concerns but he's my favorite little guy and I want what's best for him.

Would like opinions on whether a small little guy tank might make life a little easier for him in terms of food and safety. (I'v added a pic or two of some of my other platys for comparison)