oh i think it becouse they dont come in as much colors as the bettas, n yes they r ezto keep, it very rare a male paradise will kill a female when i use to keep them i use to milti spawn 1 pair in same tank i use to use a 60gal tank but the max was 3 spawns the 4th use to get eat by the outher young paradise n they r quite smart too for a fish i hhink all guorami r a bit smart so far there r red blue black n albino paradise fish i know of n there 1 call the chinese paradise all so but have only seen it in a book under good care they can grow very large