Do fish oil pills and/or the consumption of fatty fish help treat mild depression?

Fish oil-depression: Yes it can help. Fish oil and some fatty fish contain a lot of omega 3 oil which is an essential nutrient. About 50% of the brain cells are made up of essential fatty acids so a deficiency affects the brain. If you eat more fish, be sure it is wild caught e.g. Wild salmon as farmed fish have lots of contaminants. For fish oil get molecularly distilled type so it is free of pesticides etc.

Fishin' blues away: I agree with dr. Pizzo. According to small studies, fish oil may help mild depression. The dose was 1 gram a day [about 100-300 mg of dha/epa]. If you're not a big fish fan or you're vegan, you can also get dha that comes from algae.