Care for Damascus Steel knives

I got 3 knives from my Dad a few months back. I haven't used them a ton, since one is a boning/filet knife and one is a large chef knife. There is a smaller one that is more of a chopping blade. I used it last night to chop up an apple. Rinsed it off and sat it on a paper towel to clean up later. Well, later came and there was a small thin line of rust near the edge. I just scrubbed it with some hot water and a little dish soap and it all came off. Rinsed it thoroughly with hot water and wiped it dry. Looked perfectly fine this morning. Is there anything else I should do? Would a light coat of oil help between uses?