I am leaning towards oto as well, but they tend to be bleached out in the beginning so I'm not positive. Your squash does not have the characteristic marks of CAE or SAE.
Otos really are cute fish, peaceful, and industrious. They do like friends, though, and you need to supplement thier diet with veggies if there's not enough algae. They are sensitive to water params, I know this from experience. Your little fish should be a good addition to whatever tank you put him/her in.
Beth, mom of two humans, and caretaker of eight cats and seven bettas. Yes, I'm crazy.