TamaShell.com

Tamagotchi Ocean, or Umi no Tamagotchi, has an underwater theme. These devices are notoriously known for being the most difficult Tamagotchi to care for. The English-language release was incredibly limited, and so the four Western shell designs are among the most sought-after Tamagotchis, usually going for hundreds of dollars on eBay.

Blue w/ Bubbles	White w/ Seaweed	L-Blue w/ Characters	White w/ Creatures
Blue	Clear	Clear Orange	Clear Purple