The prisoners with a pink triangle identified themselves as gay (sometimes they were married to women, and engaged in very few, if any, homosexual acts). Not everyone convicted under Paragraph 175 was sent to a concentration camp; in fact, most were sent to ordinary jails. Most gay men who suffered and died in Nazi concentration camps actually wore the yellow star (because they were both gay and Jewish).
While the number of homosexuals in concentration camps is hard to estimate, Richard Plant gives a rough estimate of the number of men convicted for homosexuality "between 1933 to 1944 at between 50,000 and 63,000."
After the camps were liberated at the end of the Second World War, many of the pink triangle prisoners were often simply re-imprisoned by the Allied-instated Federal Republic of Germany. An openly gay man named Heinz Dörmer, for instance, served 20 years in total both in a Nazi concentration camp and then in the jails of the new Republic. In fact, the Nazi amendments to Paragraph 175, which turned homosexuality from a minor offence into a felony, remained intact after the war for a further 24 years. While suits seeking monetary compensation have failed, in 2002 the German government released an official apology to the gay community.