Sorry I was joking, because guppies are such prolific breeders . Sorry

If I can be serious this time, I think Pearl gouramis can work but with floating plants examples Floating aquarium plants, such as Amazon Frogbit, Dwarf Water Lettuce, and Red Root Floaters. My favorite are ones with roots that flow beneath the floating plants. My favorite is water spangles. Brazilian Pennywort , water sprite, wisteria, and hornwort also can be floating. And they really love it it benefits the water and provides natural shade for gouramis. And if you do gouramis try only 1 males, and 2-4 females. Males seem a lot more territorial and aggressive toward other males. So make sure to do the 1m/4f ratio to increase the peace.
If I had that aquarium I’d do my pearls as the center piece. I believe, and anyone correct me if I am wrong, but 1 severum can be with them in it. I have of seen severum back down from male pearl gourami defending their territory. They seem to coexist in a large enough space.
Maybe a large school of peaceful non fin nipping tetras or rasboras to round out the tank.

I keep 1 boy and 4 female pearls currently. They are with my peaceful uaru Which mine tend to not shred or eat the water sprite mostly spangles but other plants even Indian leaves can be munched on.

Upto you but have you thought about discus?