Bubble Eye

The bubble eye is a small variety of fancy goldfish with upward pointing eyes that are accompanied by two large fluid-filled sacs.It is a dorsal-less fish, and good specimens will have a clean back and eye bubbles well matched for colour and size. The bubbles are fragile and the fish should be kept separately from boisterous types and away from sharp tank decor, although the bubbles will regrow if punctured. Given proper accommodation, the bubbles do not disadvantage the fish and they become very tame. [1] It is known as suihogan in Japan.[2]

Description
The bubble eye normally has an evenly curved back that lacks a dorsal fin. The pair of large pouches of skin attached under its eyes jiggle as it swims.[1] Bubble eyes have metallic scales and they are similar to the celestial eye goldfish.[3]
The eyes of the bubble eye goldfish are normal in the young fry, but will start to develop eye bladders three months after hatching.[3]

Coloration
Bubble eyes come in many color patterns such as red, red-and-white, black, gold and calico.[1][3]

Social Behaviors
Goldfish are very social animals and thrive in a community. Not only are they a great community fish but they are great scavengers as well. It is really not necessary to add other scavengers or other bottom feeders to the aquarium when you have goldfish.

Special care
Bubble eyes require a special aquatic environment because they are relatively poor swimmers due to their impaired vision, and cannot compete with more active goldfish. Their "bubbles" can be easily sucked into the filter intake. These bladder-like swellings can also be easily damaged by any sharp-edged rocks and tank decorations.[1][3]

http://en.wikipedia.org/wiki/Bubble_Eye#_note-Johnson