Is there any jellyfish in Croatia?

Yes, there are jellyfish in Croatia. The most common species found in the Adriatic Sea are the Mediterranean jellyfish (Aurelia aurita), the Compass jellyfish (Chrysaora hysoscella), the Portuguese man o' war (Physalia physalis), the Blue jellyfish (Cyanea lamarckii), and the Lion's mane jellyfish (Cyanea capillata). These jellyfish are generally harmless to humans, but their stings can cause discomfort and skin irritation.