i have four different species of anemones (not counting aiptasia and mushrooms ) and they seem to be doing fine. now, in a tank your size, you probably could get away with a bta and lta, as long as you get them to settle in away from one another - especially since ltas tend to stay in the sand and btas tend to be rock dwelling. you may want to be sure to run carbon on the tank as some people believe the anemones will fight chemically even if they cant physically get to one another.