I will also take this time to update more on the cannonball jellyfish~
So as of right now, the Cannonball jellyfish in my 200 gallon aquarium are doing fine. The bigger one, which was previously fairly inactive, has begun to pulse around here and there. He is still healing up the scratches in his bell, but the process is going by fairly quickly. The smaller one is doing quite well, as usual. Last week it got stuck next to a heater and burned a curve shape into its bell. I removed the heater and set it in the center. The curve has already completely healed up.
Feeding - I've noticed that these jellies eat a ton of food. They are literally eating 4 times as much food as the moon jellies would. Needless to say, I cant keep feeding them the expensive decapsulated brine shrimp. I've noticed the jellies will also eat the eggs whole, unlike the moon jellies. Im thinking I may try decapsulating brine shrimp eggs myself. Ive also done some research on their natural feeding habits. Cannonball jellies tend to eat lots of oyster eggs. I may also look into buying some oyster eggs off the internet. They seem to be expensive, but I don't plan to use the oyster eggs as a staple for the jellyfish.
Tank upgrade- The tank cant run forever without a filtration system. So as filtration I will be taking a second tank (exact copy of the first) and use that as a pseudo-sump. The tank will be full of some sort of bio media, sand, plants etc. The second tank, being 200 gallons as well, will double the volume of the system to 400 gallons.
Im hoping the sump will help filter the aquarium, remove nitrates, and provide a source of food. Adding copepods, amphipods and other tiny crustaceans will allow the jellyfish to be surrounded by plankton in at least some quantities.