There is a small amount of fish oil in a cod liver oil cap, but not much.

Cod liver oil is high in A and D. Picking a version that will not give too much Vit A is important. All the brands vary. One cannot increase the fish oil portion without getting too much A. Too much Vit A leads to osteoporosis, and
increased CSF in the brain (fluid pressure). For the average person, cod liver oil is not a good choice IMO. You can get the D3 inexpensively now separately and fish oil is safer to use.

Regular fishoils do not have A and D in them. I prefer these.

1 gram capsule of fish oil has about 120mg EPA and 100mg DHA in it. (they vary)
You can buy these stronger, enteric coated, etc.
There are all kinds.
Start with one regular to see how it agrees with you. The enteric coated ones are often double strength but not always.

If you are seriously deficient you need about 3 regulars a day with food.