Any general purpose, water-soluble fertilizer will be fine. Even Miracle-Gro is OK. Since I water so frequently and generally fertilize with most waterings, I dilute my fertilizer by 1/2 during the spring and summer months and then by 1/4 in the fall and winter months. If those leaves bother you, you can either trim the yellow/brown off with scissors or just remove the leaves completely. It won't harm the fiddle.
Are you asking what plant would be suitable for your apartment? You know the fiddle leaf is a vigorous grower and is a tree, right? Even though I can bring my 25 year old "mother" plant inside a large porch to over-winter, I still trim her twice a year to keep her a manageable 7' tall.
