Clea helena and Clea Anentome helena are the most popular two subspecies in distribution. There is still biological debate last time I checked on whether there are 11 subspecies, 11 seperate species or just one species with diet changes causing subtle differences in shell size, body size and colouration.
Popular names: Assassin, Snail killer, Hannibal snail
Temp: 20-30C they become less active at lower temps
Ph: normal for snails 6.5-8 is a good range as there shells degrade at lower and higher phs
Size: 2-3cm
Diet: scavengers and omnivorous (often confused as carnivorous but they do require some external vitamins) like to eat dead flesh (not decaying however) and will hunt most snails up to 2 times their size ime 3 ambushed a 4cm pond snail that would of been more or less invulnerable if only one had attacked. They prefer catfish pellets as a dietary supplement if live food isn't available and will sometimes prefer algae and catfish pellets completely over the effort of hunting live prey.
Habits: They like to sleep after a large meal of 2-3 ramshorns or 1-2 pond snails normally for 1-3 days depending on size sometimes up to a week. They dig, you need a pair with a male and female to mate preferably with stemmed plants or bogwood, babies live in the substrate for 4 months before being seen again then ready to sell on around 7-9 months. They are not cannibals and will only eat their own species if the counterpart is sick or injured.
I have 7 adults and a bunch of babies in my tanks my little guys hunting (click to enlarge):
