The creatures without arms and without legs prefer the zir ze them family of pronouns, although they’re happy with just about any gender-neutral pronoun.
More than anything else they want you to be happy, so if you do use gender pronouns on them they won’t get super duper upset, but please bear in mind that the gendered pronouns reflect your needs and preferences, not theirs. If you do it persistently or maliciously it will probably start to hurt their feelings, so please try to remember zir, ze or them style pronouns.
We are all entities of imperfection and even their creator refers to them with gendered pronouns from time to time, so please don’t worry too much if you slip up from time to time. They’d much rather you call them her or he than give them arms and legs.