There's no limit to how long to feed fish oil...it's just a supplement anyways, so if you feel like your pup's coat is good and you want to stop, you can just stop feeding it. I feed Scottie everyday, but the thing to remember is to get fish body oil / salmon oil..NOT cod liver oil. Also, note that the dosage of the EPA + DHA should be around 300mg combined per capsule of 1000mg (you can find this on the bottle label). Feed this amount for every 15kg of your dog's weight.
Scottie is about 6-7kg, so 300mg of EPA + DHA is about all that I feed. The capsules I have are only 200mg EPA + DHA, so I give him and Kenji 2 capsules everyday.
Alternatively, if you find this very troublesome, you could get the MyBeau supplement from the pet stores. I've tried it with Scottie & Kenji and they do quite well on that too...just follow the instructions on how much to give per meal

Oh, I didn't know you used human shampoo to bathe your pup...I think you should get a good dog shampoo instead of using human shampoo. Our skin and the dog's skin are quite different, so they might not take too well with human shampoo. Currently, I use the Pet Esthe Charcoal shampoo for Scottie...it's quite good, but a bit pricey (about RM60 per bottle - but this lasts Scottie for almost a year already). We've also tried the Spa brand...the smell is VERY nice, but it doesn't last so long as I wanted to. Still, Scottie didn't have any adverse reaction to it, so it's good enough

Thanks for sharing. My fat Vodka is about 8-9kg...dunno why is he so heavy....I should start to hunt for fish body/salmon oil. Noted it shouldn't be cod liver oil....
I have limited access to pet shop here...limited choice. So my only option to shop online.
I bought tulipspet and another one which I've forgot the name. Trying to find good and suitable shampoo for him, and of coz, nice smell and long lasting.