YA Sci-fi: Book about kids in space, slaves of aliens, trying to survive/ escape. Spoiler ahead.

[Erin]

Sorry, for the vague details. I read this in middle school and it wasn't really well known. Really hard to remember the details.
- red cover, space ship pointing upper right (edge of ship or planet)
- male protagonist, all mc are teens
- theo is either the name of the mc or author
- they're fed pill food
- read between 2013-2016, published between 2010-2015

SPOILERS AHEAD:
- they all die in the end except for the love interest (or something similar)

[SBC]

Anything on the Children's and YA SF of the 2010s list?

https://www.goodreads.com/list/show/1...

Or Help! I was abducted by aliens?
https://www.goodreads.com/list/show/1...

[Erin]

Hi, doesn’t seem like it.

[SBC]

Do you have any recollection of why they were enslaved? Was it to work for the aliens, fight in an arena for their amusement, be a food source, etc?

[Erin]

I can’t really remember, but I think it might’ve been a sequel actually. It was a gift from a family friend. It began with the characters on a ship too.