Vitamins and growth hormone lol, it wasnt profitable at first, but after about 3 generations, it really really made the money. I do NOT recommend using lots of growth hormone though, after I stopped, it took forever for the babies to grow up, I was so used to instant growth. I've also found that at least for me, after the initial rush of oooooooh I can make LOADS of these fish, and tons of money, now i have more fun just trying to find the 441 at a slower pace.