Science Buddies: "Ask an Expert"

Hello,
I am a 10th grader in highschool, and I'm doing a science fair project using live moon jellyfish.
I thought I had a project idea which was to use dye to study the bell movement of jellyfish, but I don't think that project idea will work anymore...
There was also another idea of using dye to look at positive and negative spaces when a jellyfish moves, but that might be too complicated considering the jellyfish I'm getting are all about an inch big.
I still plan on using moon jellyfish for my science fair project, but I'm struggling to come up with a solid thing to do with the moon jellyfish for the project.
Any help would be greatly appreciated!

If you have enough time, you could study how different conditions effect growth of the jellyfish such as temperature, water pH, etc. Only make changes within the range compatible with life for the jellyfish, and find a way to measure their growth each day. One way would be to measure out the same volume of water every time and then add the jelly fish into it and weigh it and see how much it changes day to day.

A readout that could get you data quickly could be to count the number of contractions each jelly performs in a given time (30 sec, a min, something in a range where you could sit and count without losing track) in two different conditions (temperature, salinity, time of day, light intensity, dissolved oxygen etc etc). As Dr Sullivan said, make sure you research the normal range of conditions they can live in so you do not kill them with an extreme temperature or something.