Yes, the 555 is probably a good IC for this particular application. It will make generating the on/off signal easy.
The next thing to decide on is the system voltage you'll be using since this will determine how many LEDs can be put in series.
Then you will need to solve how you will drive that many LEDs from the 555 IC. A 555 timer can source or sink 200mA so you may or may not be able to drive all those LEDs directly from the 555's output. If it were me, I wouldn't push my luck. I would use one or more transistors to drive the LEDs. The 555's output would then just need to drive the transistors' gates and/or bases which would be much less of a load for the IC.