Advice: Why Do My Jellyfish Keep Dying?

Why Do My Jellyfish Keep Dying?

Jellyfish require good quality water and a consistent water flow in which to liveThankfully not too common a question, but one that has recently been asked: why do my pet jellyfish keep dying?

Clearly if jellyfish keep dying there is something amiss: and it is probably an underlying issue with tank management. Please review these primary factors that affect the health of jellyfish:

Jellyfish Aquarium Water Parameters

Whilst Jellyfish are more tolerant of water chemistry, they are sensitive to water salinity, PH and any water additives.

Using an hydrometer, ensure water salinity reading is at 1025sg or 34-35ppt, and any water added during water changes is salted RO water that has been either bought as pre-mix or mixed at the correct salinity levels for at least 24 hours.

PH should be in the 7.9 - 8.4 range

Temperature should be 13 - 26°C - generally a degree or two below ambient room temperature negating the need for heating; though chiller attachment may be required if the ambient temperature regularly rises above 25°C

Under no circumstances:
-  place or attempt to keep jellyfish in tap water
-  add any water treatment or enzyme treatment to the water as jellyfish are very sensitive to them causing distress and harm.


Initial Jellyfish Aquarium Set-up

When a tank is first set up the water need to be cycled (matured) for at least 10-14 days. When maturing in a new set up, it is natural for tank water to go through an ammonia and phosphate 'spike' as the water reaches its normal mature state (for full water chemistry readings see our downloadable husbandry guide). High ammonia levels will cause ammonia 'burn' to jellyfish and if jellyfish are introduced too soon they may well succumb to this.


Acclimatising Jellyfish to the Tank Set-up

When first adding jellyfish to your tank it is vital that they are acclimatised properly by floating in the bag they arrive in for 30-40 minutes to match water temperatures before releasing the jellyfish into the water. It is important that the release be made totally underwater so the jellyfish don’t come into contact with air.  Failure to acclimatise for sufficient time may cause thermal shock (sudden temperature change) to the jellyfish which can be fatal.

Jellyfish might not be wholly active immediately after introduction to a new tank environment or total water change, but they should begin to act naturally again within approximately 60 minutes.


Confusing Lack of Water Flow with Fatality

If your jellyfish appear motionless at the bottom of the tank, make sure there is sufficient water flow through the aquarium for them to move within. It is not uncommon for flow pipes to become dislodged when working on the aquarium, thus restricting or disconnecting the flow entirely: a factor easily overlooked but easily resolved.


"My Jellyfish Just... Fell Apart"

This sounds like the start of a bad Vaudeville joke but unfortunately it is, on occasion, a reality as like any other living organism, jellyfish can be subject to bacterial attack. Normally, healthy jellyfish come to no harm but if the specimen is damaged or stressed then it can, being 96% water, succumb to bacterial attack which in extreme cases can lead to total disintegration in a matter of hours. Aurelia sp. (Moon Jellyfish) are particularly prone to this if not cared for properly.


Why not: