You can see the number of animals killed per person per year in different regions of the world at The Veganalyser (https://www.vegansociety.com/sites/default/apps/veganalyser/) of The Vegan Society. This is the most sophisticated veg*an calculator I have seen.
When you choose the second option (Already vegan?) and choose the region, and put years (1 year, or 100 years if you want a more accurate number), you can see the number of animals consumed per person per year by different species of animals.
For example, South Asia contributes to the death of 105.58 animals per person per year. 100.41 were fish. While Northern America responsible for the death of 47.85 animals per person per year. The consumption in East, Mid, West Africa were 15-17 animals per person per year. (Southern or Northen Africa are higher) Most animals consumed in those Africa regions are fish as well.
Of course, there are limitations to this calculator. For example, all Asian regions were estimated to slaughter 100.41 fishes per person per year, all African regions 12 fish/person/year. For information on the calculator, see https://www.vegansociety.com/whats-new/campaigns/veganalyser/about-veganalyser
Nonetheless, 100 fish/person/year in Asia estimate does not seems to be overestimated. According to the fishcount.org.uk, 0.97-2.7 trillion wild fishes are slaughtered every year. That is 130 fish/person/year.
Conclusion: The concerns of meat eater problem is not ‘negligible’ in developing countries. As about 50% of fish are farmed (http://www.livescience.com/5682-milestone-50-percent-fish-farmed.html), the suffering farmed fish will endure during the course of its life should be taken into account as well.