Happy vs. Sad Jellyfish
The physical differences between HAPPY (healthy) & SAD (unhealthy) moon jellyfish.
SAD - "Tentacle Balls"
The tentacles become knotted and tangled around the perimeter of the bell.
Not enough flow in the tank. The tentacles will tangle when the jellyfish don't have adequate support from the current of water flowing in the tank. This condition is reversible once the problem is addressed.
hAPPY - Fine, Untangled Tentacles
Increase the flow rate to support the number and size of your jellyfish. The more jellyfish you have and the larger they are will require more flow to support their belling requirements. You will need to increase the flow rate as your jellyfish grow.
SAD - "Flying Saucer" Bells
In this sad instance, jellyfish are opaque & slow to bell, if at all. The radial canals are indiscernible & unnoticeable. The perimeter of the bell is curled under with the oral arms hanging straight down.
Improper acclimation can cause the perimeter of the bell to curl under & relax the oral arms. This condition is a permanent one once it has occurred.
Constant & excessive target feeding with acidic and concentrated foods can desensitize the jellyfish & cause the perimeter to curl under & deform the oral arms. In some cases, it can cause a sort of arrhythmia, where the jellyfish no longer bells normally, but in a circular pattern (a.k.a. "hoola -hooping").
HAPPY - Clear, open bells
The jellyfish has a clear bell with defined radial canals (the branching vein-like features that run throughout the bell from the stomachs to the outer perimeter). Visible radial canals indicate that the food is being fully metabolized throughout the jellyfish; therefore, supplying the jellyfish with proper nutrition. The perimeter of the bell is smooth and open, not rigid and curled. The tentacles are relaxed and soft.
Take at least 15 minutes to acclimate the jellies to the temperature of your tank, and then another 45 minutes acclimating them to the water chemistry of your tank through small water exchanges within the bag before releasing them. This will allow the jellyfish the necessary time to adjust their internal chemistry to that of your tank
Do not target feed your jellyfish on a daily basis. If your jellyfish cannot feed on their own, you need to look at what you are feeding and why you need to target feed them. If the food is not neutrally buoyant (i.e. stays in the water column and does not float or sink as soon as you put it into the tank) and you need to target feed them, be sure the food you are target feeding is not concentrated or in any way acidic, as this will cause desensitization and a "balling up" of the jellyfish, causing them to become rigid and inactive.
SAD - Bell Eversion
In this sad case, the bell has flipped up and over the top of the bell of the jellyfish creating a saucer or cup-like look. The oral arms are hanging down and not tucked up under the bell as per a healthy jellyfish.
(sometimes referred to as "Inversion")
Malnutrition leads to thin jellyfish that are prone to flip due to weakness.
Flow rate too high. The jellyfish are spinning like socks in a dryer and never allowed to bell or swim naturally, which means they also are not eating properly and this leads to malnutrition.
Flow rate too low. The jellyfish are unable to bell properly due to the lack of "support" they get from the water movement. Belling problems lead to eating problems--if they can't bell properly, they can't eat well, either, which leads to malnutrition and thin, inverted jellies.
Physical Damage. The jellyfish was stuck on the bottom or side of the tank for over an hour and the bell was physically damaged.
HAPPY - Rounded Bells
Feed only nutritious, neutrally buoyant foods daily to maintain proper cell growth and function.
Adjust the flow rate just enough to keep the jellies off the bottom of the tank, but not so much that they are being propelled around the tank. Watch some of our videos to get an idea of what the proper flow rate looks like.
Maintain the proper flow rate and the jellies will not have the opportunity to get stuck for long periods of time.
SAD - Bell Erosion & Tears
Toxic Water. Ammonia and/or nitrite is in the water. A simple water test will indicate if this is your problem.
Physical Damage. A siphon tube, turkey baster or scrub brush has come in contact with the jellyfish.
HAPPY - Smooth Bells
Allow your tank to go through the complete nitrification cycle (about 4 weeks time) and you will not have any issues with ammonia or nitrite toxicity destroying the delicate tissue of the jellyfish.
Always keep one eye on the end of a siphon tube, turkey baster or scrub brush! Jellyfish do not get out of your way when cleaning the tank so you should keep an eye on where they are at all times while cleaning the tank.
SAD - Holes in the bell
There are a couple different types of holes that can occur in the bell of the jellyfish. One is a smooth-edged hole occurring directly between the stomachs (or directly over one stomach in particular).
HAPPY - Smooth bells
Always dilute foods with some of the tank water and feed in small doses. Some foods on the market are very concentrated and acidic. Dilute them for best results.
Keep frozen jellyfish food in the freezer at all times and only take it out right before feeding time. Do not keep frozen food in the refrigerator--Freezer Only.
SAD - Cloudy Tank
HAPPY - Clear Water
Do not disturb the filter media during or after the cycling process as this kicks up the bacteria into the water column creating the cloudiness.
Do not interrupt the cycling process once it has started (i.e. ammonia and/or nitrite are present in the water)! Any water or filter changes conducted after the cycling has begun interrupts the cycle and causes the bacterial bloom.
Do not pour distilled or RO water down the filter box as this will kill the bacteria and cause a bloom.
Do not do more than a 20% water change after completing the cycling process as this can disrupt the balance in the filter media and cause a bacterial bloom. If you need to do a large water change to reduce nitrates, for example, plan on doing 20% water changes every other day for up to a week, if need be. Do not do it all at once. Stability is the name of the game. Do water quality adjustments in small increments so you don't create an unstable environment for the jellies.
All of the pictures used here are from Google.com, customer submissions, and our own database.