Mags are good pumps, but the larger models tend to run a bit warm for my taste. For our larger setups, I've been using external pumps (I'm really liking Little Giant ATM). Our 100 gal utilizes a LG 4-MDQX-SC for the mains and an Iwaki MD40RLT as the CL pump. The LG runs thru a 1/4 hp chiller and a SCWD, while the Iwaki pushes 3 returns.
We keep a fuzzy and a D. barberi together in a std 60 gal with no real issues, altho the fuzzy is indeed the dominant lion. I wouldn't keep either with our adult volitans tho...I'd be afraid that she would slurp them down and ask for seconds.