So I was thinking about building a deep water camera housing. The housing would be filled with a non-conductive fluid to counter the pressure at depth.
Although fluids like purified water or propylene glycol (anti-freeze mixtures) are stated to be non-conductive, they become ionized when in contact with metals and plastics, thus gradually conducting electricity again. There are ion-exchange resin products that are supposed to keep the fluids de-ionized though. Source: https://www.electronics-cooling.com/2015/12/tech-brief-low-electrical-conductivity-liquid-coolants-for-electronics-cooling/#
So while the electronics might survive being emerged in liquids for a day, what about the 3V lithium batteries that power the camera? Do you expect this thing blowing up in my face in any case, or is there a possiblity that this might work?