Have you tried dither fish? Something smaller than the multifasciatus but still able to take as good as it gives? I’ve had Cryptoheros cutteri and Panamius panamensis in with my a couple large centrals. The cutteri are kind of a dicks and they give way more than they receive from the lyonsi in one tank and the melanura group in the other. I don’t think the world needs more than but the gold standard for dependable dithers are Amatitlania nigrofasciata.