white clouds

I have been watching my three white clouds for a long time wondering why the fat one never gets thinner. Even when I feed them less- letting them subsist off algae and aufwuchs most days of the week (the guppies are totally fine with this and I spot-feed the paradise fish)- this one doesn't slim down. The other two flare their fins and dance broadside to each other so I think those are males and the fat one a gravid female. I was reading up on it the other day, info says white clouds breed as easy as guppies, but need soft plants to spawn in, like java moss. I wondered if subwassertang would do. So I transferred the two mature female guppies into my 33L, and moved the white clouds into the half-filled 20H- swapped 'em.

After a partial wc. Did another large water change on a day of thunderstorms, and then added some new leaf litter too (because the white clouds were dashing around displaying to their reflections in the bottom glass). I saw lots of display and chasing, and thought the third fish started to look a bit less fat? but can't be sure.

They certainly have nice colors

Caught one male with his fins spread

but it's been days now, the fat fish is still fatter than the others, and there's no sign of fry. So I think this individual is just a glutton, or has a parasite load. Thinking of dosing the tank with prazipro or general cure.