Once it was a common usage to not eat meat of a Friday.
Abstaining from meat is a usage part of the Catholic faith, it imposing to not eat meat in the "lean days", that is to say Friday and other particular days in the Calendar, for example Whit. Fish is allowed during these days of abstinence, and it is for this reason that Friday is the day when in countries having a Catholic majority one eats fish. Also, here in the hotel we observe this tradition, even if very few others now respect the rule. It is one of those instances when conformism becomes anti-conformism. The again, if we were to eat less meat in general, we could hope in a better world, but that for the moment is another subject to approach.