The NSI Smithsonian Jellyfish Tank. This blue LED Lit tank will show imitation Jellyfish and you will watch a Bloom of Jellyfish Swim. Live Jellyfish come in all shapes and sizes. Most jellies range from less than half an inch (1 cm) wide to about 16 inches (40 cm), though the smallest are just one millimeter wide! The largest jellies are the Lion's Mane Jellyfish), which on average are around 3 feet wide. This colorful LED tank is perfect for the Bedroom, or Den. This is the perfect gift for anyone, Male or Female.