Well, I am taking them too and did a TON of research, so I feel like an expert.
First off, if you taste a nasty, fishy taste then the oil in your capsule may be rancid. If it is a *normal* fishy taste than it is the oil. If you have any type of reflux or GERD problem, you can't avoid the burps!! Fish oils (also flax and hemp) should always be taken with meals as they work better with your other nutrients.
Also ensure that your fish oil supplement contains vitamin E. Essential fatty acids will cause free radicals when they are broken down in the body. Vitamin E works with this issue.
The best supplements are:
Nordic Naturals
Carlson's Fish Oils
Health for Life
These three brands are all lemon flavored. The Nordic Naturals and Health for Life all contain vitamin E in the product, so you do not have to add another supplement. Also, it is best to refrigerate the product once you open it. These oils are very delicate and unstable and go rancid quickly.