The phrase "fixed with" implies that something has been attached or secured to something else. There are several synonyms that can be used in place of this phrase, depending on the context. For example, "fastened with," "secured with," "attached with," or "affixed with" can all be used to convey the same meaning. In addition, "mounted with," "installed with," and "connected with" can also be used depending on the situation. When trying to diversify your writing or simply looking for a fresh way to describe something that has been attached to another object, choosing one of these synonyms can be an effective way to do so.