Booted axie?

AUTO CORRECT BUTCHERED THE TITLE:BLOATED AXIE IS WHAT ITS MEANT TO SAY
Never had problems with my Lucy before, but she's..well. I can only assume it's bloat.

4-5 inch Lucy, I only assume it's a girl.

I recently put sand in for the first time and got s brand new filter, a sponge filter with s spray bar! Yay. I was watching my Aries and noticed that the Goldie was skinny (always has been) by the Lucy is extremely pudgey. I fed them today, the last two cubes of bloodworms (they have been eating one per lotl' so I'm working on getting them night crawlers, after failing with red wigglers) and I noticed the Lucy looks like she ate EVERYTHING but I know she didn't, I watched them eat. What caused this? Did she eat sand?? Should I be worried?

She's always been a bit 'round in the tummy' but never this big..

Don't panic.
Bloat is a symptom rather than a disease, and if it is just the stomach then the chances are that your little one is just a bit constipated. She may have ingested some sand, but she will be able to pass this and it won't cause impaction, that's why we use it.
Just make sure that your environment is perfect and keep an eye on her, but the chances are that she will do a massive poop in the next day or so, then be back to normal.
Please see the link for information.
Caudata Culture Articles: Bloat
Some of the more experienced keepers may have better advice for you, but just keep an eye on your little one for now, until something else happens or someone else gives more advice.

By the way, I know I shouldn't laugh because obviously you are concerned about your axolotl, but the auto correct phrasing of the title of the post intrigued me, then when I realised that your axie was pretty much ok the title made me chuckle. I now have a mental image of your little one in 4 very stylish boots, and you posting pictures of her cat-walking up and down the tank to model her new boots.