I am trying to make fish leather. I really want to use some - fill it with water, perhaps make some fish skin water balloons. I have sourced some form Walter Reginald in London, but I am struggling to ascertain what chemicals are used in the tanning process, and I don't want to run water through heavy metals. So I thought I would try and make some of my own.
So, you have to de-scale, de-flesh, and 'tann' in a mixture of oil and egg yolk (1 dl oil : 1 egg yolk) or use 50% urine and 50%water ( preferably from a boy) see: Tanning Fish, I left mine overnight to tan, have given it a good cold wash and it is drying now...
These patches where the skin colour comes off are not holes - they have a pretty tough translucent and patterned skin on them. I didn't realise the coloured part of the fish was behind this - and not on the outside.
The flies are after the leather.