That's a parallel wiring set-up, which was the way to go on AC circuits. Red's are hot and the yellow is a common.

Listen, I have a few extra icecap end caps if you want them (2 sets I think).

I also have a small 1.5" frag of some kind of green Acro that's been knocked all around my tank and still going strong. It's nothing special, but it's very hardy. You're more than welcome to it once you're tank's acclimated.