Mini orchid- B. hirundinis or B. purpurascens?

[gnathaniel]

Though both species are what I would call miniature, hirundinis is vegetatively about 1/2-1/3 the size of purpurascens, with more colorful and proportionately larger flowers (but plainer foliage). hirundinis does best for me in intermediate or cooler temperatures whereas my purp died when I let night temps drop below 55 F, so purpurascens may be better suited for the temp range of your tank.