Is it okay to give a dog fish oil?

So it's something I've found online and I've been doing that for about two weeks. It's improved both my dogs coats, their dry skin, and my puppies weepy looking red eyes are now normal. I just want to make sure it's safe because I give them one 1000MG pill a day (anchovy, mackerel, and sardine oils). One dog is about 30# and the other 50#.