Doberman I used to have.
His name was KC but I often called him Glue because he never left my side when I was home.
Best one I've had the privilege of sharing time with.

I have pet fish and if I get tired of their names I can change them and they will never know!

Buddy. I always call him buddy.

His name is Barney but he’s also known as Barn, Barn-Barn, Bubba, Bub and The Most Handsome Boy Ever! If he’s in trouble then Barnifred James

Sooooo many

Anya: Lasagna, crazy, big butt
Koda: doka, docalax, moron
Nyxon: Nyx, Nyxie, Pixie, titty, piddy toddy
Persephone: Purrcy, lucifur, psycho, puff, slinky

I sometimes wonder why I bother to name animals as they end up with a whole list of nicknames. They learn to answer to them all -- even Fred, which is what they get called when they're naughty. I have no idea why, but that's become the default term.

Yes, I call them sweet boy and sweet girl. They answer to their names or nicknames. My husband calls them killer and vicious, of which they are neither.

Phineas is called Phinny-cats, Phins, and Carpet Snake

Ferb is called Ferby, Fur-baby, and Fluff n Stuff

I love all three but the dog is Shithead. Old kitty Madge is Mo. Slightly less old kitty is Asshole or Succubus... depending on the situation.

Sir Loodwig Van Barktoven the 3rd also goes by Ludgate, LudDog, RatDog, Little Doggo & El Puppers.

I don't have any pets as I live in an apartment, but my car is called Claude. And my, ahem! ...y'know, I call him little Mike. Too much information?

My cat’s name is Veronica but I call her Nonners. Her sister, Betty, passed away last July and I called her Beeps.

Multiple names, most involving rhyme and/or aliteration.

Each of my three cats has several nick names based on personality, actions and derivations of their original name.

I have a big fat all white male cat, one blue eye one green eye. His name is Ranger ( he came with that name) but I call him Boo.

Ofcourse my Connie girl is family.

I call my dog Dingo sometimes because she's about the same size and shape as a Dingo, even though she's not the right color.

Yes, but none of them are suitable in public!

My miniature pinscher/miniature schnauzer named "Koi"... is "pinhead", and my olde english bulldogge named "Duchess" is "melon head".

I always do

I never did have nick names for my pets but that was years ago and today I am alone without any pets. This posting makes me realize that both my daughters have nick names for their pets. I'm not sure if they always did or not. IDK?

I have a cat named Monkey and I call her Not helpful Monkey. Because she isn't.
<<<That's her as a matter of fact, lol

Their names evolve. My older cat, Oreo, is called Bitchy Kitty. The younger cat, Shark Bait, is called Kitten or Precious. My Dog, Forrest Tucker Snickerdoodle Floofy Weasle Rossnik is called Pooper Do.

LOL, nicknames and songs.

My cat is Opal, but her nickname is Opie, Opus, Opie ca poky My old cat was Loki, but I called him Loki poke.
My dog is Tess. I call her Tessie Lou, Tessa, or the Contessa.
My horse is Hobbit. I call him Hobbs, Hobbity Bobbit, or Hobble.
My other horse is Ceal Garagh, which means Illusionist. We call her Keely or Keekee.
My daughter's horse is Cushla ma Croi, which means Beat of my Heart. We call him Croi, Creaky, or Creaks.
We have a pig called Ginger, and we call him Gingy, and one called Thorn, and call her Thornie or Thorndike.
My goose is Gerald. He doesn't really have a nickname. I think he would be offended. We have lots of critters. More pigs, goats, chickens, geese, ducks and a pregnant donkey. They all have names, but no nicknames. A lot of the chickens, ducks and geese have the same name, although, the ones who stand out have their own.