My girl is also 6 months now and i've started her on bellamy's organic rice cereal 2 weeks ago.
Started with just one tbsp of the dry cereal mixed with ebm, now giving her 2tbsp once a day.
You may like to try this rice cereal as my girl looks it alot.
As for porridge, I'm not sure about introducing porridge with fish so early.
It's always good to start one solid food at a time ie. Get him used to plain porridge first then slowly introduce one vege, followed by one meat, then fish. As I understand it's good to introduce meat only after 7th month? Maybe experienced mummies can enlighten me here? Thanks.