Ah ok. If you have a ton of guppies in the tank then I wouldn't add any other small schooling fish. Could be too much and also could just look like a bad mix of fish lol. But right now I'd say the tank is well stocked.I will check out the fish you mentioned and they compatibilities! O. O yes, I current have in thay tank (forgive me if I get the English names incorrect) :
Antenae placo ( Antennenwels) (male)
Mosaik placo (Mosaik panzerwels) (female??)
1 dwarf gourami (male)
2 swordtails (m/F)
And a ton of guppies ^~^
I was thinking about getting 1-2 more female dwarf guramis for the male ^~
PS.
I've heard that dwarf furami es can be very territorial, he seems to be rather calm though! The only times I see him. Chasing anyone is if they get to close, but other than that, he just swaims around and minds his won business!
I've read several times that pairing them with a female or two can also calm them down since they are schooling fish?
The only thing I'm personally concerned about is the hardness of your water. Your pleco is a software fish and most gouramis are also software. But swordtails are from medium-hardwater. And guppies can live on the mid-higher end of soft water (meaning it can live in water that is almost hard or IS hard)...
Most of the time, fish kept in the wrong water hardness die early. And sometimes it can be a painful death. Hardwater fish have an organ that can process hard water but in softwater fish, minerals build up inside and lead to kidney failure. And if hardwater fish are kept in softwater, they don't have the minerals needed for proper health.
Just a heads up is all. Not saying you have to get rid of those fish or make any changes to water chemistry. If your water is medium-soft your fish should be fine