Found a little gem the other day (from christmaslightsetc.com) in my constant search for new and fancy bulbs. These are replacement bulbs for a c7 strand (which I have several of, and use all around Halloween because the bulbs can be changed out for different colors), but these bulbs are the color changing ones--and LED. Which means awesome things for my wattage. I've been trying to convert as many of my lights over to LED as possible--easier on the wiring of the old house.
They were a little pricey (~$1.60 a bulb) but because they're LED, they'll last a lot longer than a normal bulb would. They're also brighter, and are exactly what I need for my jellyfish this year. I was going to resort to just using the ice cube lights, which would have been a bummer to have to switch on manually. These I can put on a timer--if they're as awesome as I'm hoping--fingers crossed!