Keep in mind that older males can pass the 8 inch mark by a good margin. I had a male that hit 9 inches (excluding tail of course), and have seen an 10+ inch male at my lfs. Highly aggressive, breeding pairs can take down deceptively large tankmates. My first pair (male 9 inches, female 4.5 inches) completely cleaned out a 90g. In a 125, tankmates are an option even with a pair, but as mentioned before, limit to other medium-large robust cichlids and perhaps some of the larger species of schooling characins (silver dollars, nurse tetras, etc).