I guess I caused a lot of confusion with using the word 'predator'
I'm open to adding any fish that will help keep the guppy population controlled.
I do plan to upgrade in the future (I recently went from a small 55L to this 90L), given I'm still somewhat new to the hobby I didn't want to go straight for something like a 180L

I do plan to upgrade in the future (I recently went from a small 55L to this 90L), given I'm still somewhat new to the hobby I didn't want to go straight for something like a 180L