I agree on the concerns with tilapia. I don't eat it because of the fact it's a "garbage eater" (will eat whatever it's fed), so there can be concerns about what its flesh is tainted with if it comes from questionable sources.
I also think salmon is a great choice! 10 month old DD loves salmon. I don't make it too spicy for her, yet, though -- I usually just roast it and dice it up with some veggies, spiced with dill or maybe lemon and pepper.
That said, this recipe is DELISH and you can spice it up as much as you want (add in chilis to the bell pepper).
http://simplyrecipes.com/recipes/salmon_fish_stew_brazilian_style/
Finally, this is the FISHIEST of fish, but mackerel goes over REALLY well with kids, in my experience. It's also a fav with DD, and my nephews (2 and 8 months). I get the tinned stuff, which is canned in oil so there's plenty of healthy fats for growing kids. The sodium in the brand I buy is not high, either (make sure you check if you want to try this).