Some nitpicking: the passphrase is not as good as it seems. It consists of two parts ("horse in a box" and "riding a fish") both of which can be found in e.g. Google's n-gram corpus [1]. The Google's corpus has on the order of 2^32 n-grams so even assuming you chose these two at random, you get only 64 bits of entropy. There is also some punctuation (let's be generous and say it gives 10 bits), so the entire passphrase is about 74 bits of entropy. While very good, this is probably not enough to protect your bitcoin life savings or a truecrypt container that can implicate you in a serious crime (the reason being that Moore's law may well make 74-bit passwords easily crackable in 10 years or so)
For comparison, the first password you provided (16 random alphanumeric characters) has 95 bits of entropy.
