My guess would be that people aren't answering because a) they're at work and it's not an "opinion" type of question, and b) they don't know more than can be turned up by a Google search. But your question got me curious enough to do that Google search for ya.

So, from my vast, recently acquired Wikipedia knowledge, I'd say a guarded yes, it's somewhat redundant. Your fish oil ought to have a good amount of DHA in it already. But if you want a better DHA:EPA ratio than your fish oil might have, I could see supplementing. Or getting a better fish oil.

http://en.wikipedia.org/wiki/Docosahexaenoic_acid#DHA_and_EPA_in_fish_oils

Try this:

It's a great combo of Fish Oil and Vitamin D

http://www.lifeplus.com/Product_Details.asp?CatID=1&PN=4999&PSID=1&WSID=1