My three riding horses are all registered - a first for me as our others aren't. So my three horses come with registered names. I used to think TB registered names were often yucky (Slick Sheik, anyone? - that was the TB registered name of one of my daughters' first horses) until I encountered QH registered names. My first QH was Walla Bars Bonanza - sort of weird, but related to his pedigree and not too bad. His nickname was Noble - he came with that name and it suited him.
But how about these three registered names - Silent Dawn (TB; always makes me think of dead birds; the name has nothing to do with the names of her ancestors); JTS Speed Glo Cody (QH); and Driftin' to the Money (QH; double yuck). At least both the QH names are related to their pedigrees, and Red was bred to be a money-winning barrel racing horse.
Dawn came to us with her nickname. Again, it's not one I'd have picked but it's OK. Pie could have been nicknamed Cody but I'm glad he was called after Jimmy Stewart's movie horse Pie (not the Pie from National Velvet) - he came to me with this name also and I like it and it really suits him. A side note - I rarely change horse's names when they come to me since they almost always know their names - there have been two exceptions, the first being Lily - she came to us nicknamed Lulu, which was just plain awful - Lily is very close in sound so we changed it to that.
Red's nickname when he came to me was Drifter, and he's the second case of a name change. I'm sure the name was intended to draw attention to his double Driftwood Ike breeding, but I always disliked it - for me it had overtones of shiftlessness. He also came to me with some serious behavior issues which took some time to get sorted out. But once they did, it seemed that a name change in celebration of his personality transplant was in order. Red is a pretty common horse name, but it suits him and he seems to like it.
But in addition to their nicknames, all three have additions that I regularly use when I'm with them. Dawn is always Dawnmare; Pie is always Pie Pie; and Red is always Redman. Does this happen with you and your horses? What are your horses' nicknames, and do they also have "secret" nicknames?