1.Most Cnidarians do not have eyes or any type of developed organs. 2.The phylum cnidarian consists of about 10,000 species of simple animals found only in marine habitats. 3.It is best not to touch very small jellyfish, or any jellyfish AT ALL. Especially do not give them names like "Squishy" 4. Jellyfishes are made up of more than 95% water and they have no brains, blood or nervous system. 5. Jellyfish can have up to 800 tentacles. 6.Cnidarian comes from the Greek word, which means stinging nettle.