I googled it as well and got mixed reviews.. someone said that salmon oil is better, another said canola oil. Then I also read that too much can cause vitamin A deficiency. So now I'm just worried in general She's not uncomfortable at all nor is she suffering, she has just been having more hairballs lately. It's also been REALLY hot here, and my A/C is broken so I'm sure it gets quite warm in my apartment when I'm at work (I do leave fans on for them) so she might not be drinking enough water and she might be shedding more. So even if I don't do the oil thing, I'm going to start supplementing their diets with some wet food every night (which Tilly will LOOOVE.. she mews like a kitten when I ask her "do you want some fishies???" - it's too cute )