Lions are a better choice if yer thinking ahead. You can keep any fish with a lion as long as it wont fit in its mouth. BUT...triggers, especially clown triggers, dont do so well with the "sharing a tank" thing. They can get quite evil and end up eventually destroying everything in yer tank. And u cant keep the two together, cuz the clown has maybe a 75% chance of ripping yer lions fins to shreds. Maybe a different, more passive trigger would be better, like a niger or sumthing of that sort. But id say u can keep a full grown volitan in a 125 whereas ud need a 190 for a full grown trigger. It depends on which one u really want, and then you have to wrok with them on getting other fish. If u want a nice community tank, id say get a lion (unless you want smaller fish) the cons for both the species is that wen they get full grown, a lion will swallow the smaller fish, or a trigger will simply bite em in half. I personally would say go with a lion cuz im a lion guy, but they are kinda boring if u dont respect them. So do some research, see waht you want and then come back. But for right now if u got a dwarf lion then that could live for life in yer 75 no problem. Antenattas are a good choice....