Blue velvet nudibranch
 

Anyone in Calgary ever seen one in action? I can't find one anywhere....

Back when I had flatworms I tried one , as advertised they start eating the immediately . But in most cases they die of starvation before they kill all the worms . So I ended up siphoning them out daily and eventually they went away . Had them for a few years as I refused to use flatworm exit as its to risky imo .