Okay, it might not be THAT dramatic, but the amount of flow in your tank does have a huge impact on the health of your jellies.
Jellies are considered planktonic, which means they cannot swim freely against a current and therefore rely on some sort of flow to stay afloat. However, this doesn’t mean they need to be propelled through your system at mach 3. When you make your jellies race each other, nobody wins!
When the valves in the behind your EON jellyfish tank are fully open, like the one on the left side of the picture above, the your jellies will move so fast that they won’t be able to catch their food efficiently, nor will they be able to hold onto it if they do capture some. It’s almost like they’re getting motion sickness on the tilt-a-whirl at a carnival… forever. Understandably, they won’t react well to starvation and will stop belling and start shrinking until they die.
Instead, keep your valves at about 50% flow like the picture on the right. This gives them enough circulation to stay off the bottom of the tank while still giving them enough freedom to bell around and hold down their lunch.
Just remember: if the flow is too high, jellies die, moderate flow, good to go!