The ones i had could easily take a weekly water change. It was when I first introduced them into the tank that there were quite a few casualties, even after drip acclimation.
Could get ember tetras. They're only the slightest bit bigger and once they acclimate to the tank, they're a really nice bright orange that stand out wonderfully against plants if you have any. They're also pretty hardy, if anything, they were tougher than the common neon tetras, which is also an option though, they're significantly larger and more active, so i'd advise a bigger tank.
Pygmy Cories are nice. They're not particularly colorful but the way they bumble around the tank all day is adorable. If your sand or gravel are dark, they stand out really well.