The skins we use for making leather (including the majority of fish skins) come from humanely slaughtered animals for the meat sector. All animals (including fish) are stunned prior to slaughter and experience no pain. Sure there maybe one or two rogue operations and there will be occasional errors in the slaughter process (which can be found on YouTube) but generally the level of slaughtering procedures and the government control of such operations is humane and well controlled.
The concept of skinning animals alive to obtain the skin is not normal operating practice in the meat sector. The websites who write this nonsense are so poorly informed it is surprising they have the gall to write such rubbish. The article on fish skins (www.care2.com – Something fishy and really cruel about Luxury Leather new trend) goes on to explain that tanning takes 30 days in baths of chemicals that are dangerous! The level of misinformation that is allowed to go unchallenged on websites is abhorrent. Tanning of fish skins may take 30 days from start to finish and will involve the use of controlled chemicals – but these will not be harmful to humans.
I would be against any animal being skinned alive for commercial benefit – but skinning alive is the thing of horror movies, not the dirty background of the leather sector.