Ryukin

Ryukin goldfish are distinguished by their very short body and protruding hump behind their heads. This variety comes in red, black, white, or a combination of colors, but they are very poor swimmers, so your aquarium can be smaller (10 gallons per fish) in order to accommodate their lack of vigorous motion. Many poor-swimming goldfish need to be fed more in order to satiate their high caloric burn from swimming exertion.