Whether it’s your first jellyfish or future additions, the aquarium must be acclimated to its new inhabitants. It’s essential that any new specimens introduced into the aquarium match the existing water parameters.
To achieve this, gently place the new jellyfish into a container filled with the water from their shipping bag. (Keep in mind that more water will be added, so the container should have extra capacity.) Gradually add small amounts of aquarium water to the container using a scoop. Repeat this process at intervals of at least 5–10 minutes. Typically, allow one hour per degree of difference in temperature or salinity. Another method is drip acclimation: use a silicone tube to siphon aquarium water slowly into the container holding the jellyfish.
If there’s a significant temperature difference—especially in summer—you can float the sealed bag with the jellyfish in the aquarium to equalize temperature, while slowly adding aquarium water to adjust salinity.
The goal is for the jellyfish to acclimate gradually and experience minimal stress.
Use a thermometer and a hydrometer/densimeter/refractometer to check that temperature and salinity are aligned.
Once the parameters are equal, you can gently transfer the jellyfish into their new home.
To restore the water level in the tank, either top off with clean artificial seawater matching the tank’s parameters, or reuse the acclimation water if it remains clean.