A responsum from a British Chief Rabbi concerning why Jews eat fish, wear wigs, etc.

There is a chapter called 'The Jews' Fish-Market in London' in Frank Buckland's Notes and Jottings from Animal Life (1882). Writing in 1878, he discusses his impressions from visiting a Jewish fish market. Almost everyone spoke in a language he didn't understand and all signs were in what he thought were Hebrew. It was right before Passover, and he noticed Matzos being packed and sold. He noticed fried fish and cucumbers in saltwater (I can't tell if these are pickles or not) being sold, and he especially noticed women wearing wigs:

The thing that struck me most was the custom of the Jewish women wearing wigs. When standing at the corner I counted no less than nine Jewesses wearing wigs. Some of these wigs were brown and some black. They were apparently not worn for show purposes; some were low down on the forehead, some all awry, and some at the back of the head. I cannot conceive how the Jewesses can wear these hideous wigs. I believe this custom of wearing wigs is not confined to the poorer classes.

He then quotes a letter from Rabbi Hermann Adler, who would go on to become the Chief Rabbi (and was already assistant to his father) in which Adler explains all these phenomena to him:

My learned friend Dr. Adler, the eminent Jewish Minister, and son of the chief Rabbi, wrote me to the following effect:—' We Jews eat fresh-water fish simply because we like them, and because the poor can afford to buy them better than meat, which is more expensive. We eat cucumbers simply because we regard them as a delicacy, and most of our poor come from Holland and Germany, where everybody eats cucumbers.

'The origin of eating fresh-water fish and cucumbers may possibly be derived from the fifth verse of the eleventh chapter of Numbers: "We remember the fish, which we did eat in Egypt freely; the cucumbers, and the melons, and the leeks, and the onions, and the garlick."

'With reference to the wigs worn by the Jewish women, these wigs are only worn by married women, mostly Polish. The object is to cover the hair so as not to be so attractive as before marriage.

'Our Passover is the eating of unleavened bread, but the Paschal lamb is not offered any more, as the Temple is destroyed.

'The language you heard in the market was not Hebrew; Hebrew is not spoken any more as a living language. The conversations you heard were carried on in a kind of German or Dutch mixed up with a few Hebrew words. The advertisements in the shop windows were not Hebrew, but German in Hebrew letters. A few Hebrew words are used, such as kosher, "that which is lawful to eat." Meat of an animal that has died without being properly slaughtered, or suffering from any disease, is called tryfer.'