The red-bellied piranha (Pygocentrus nattereri), a species of piranha native to South America.

piranha solution, a mixture of sulfuric acid and hydrogen peroxide.

vivid / skillful / colorful

a piranha

the color red

to know, be aware of / to learn, acquire, / to be acquainted with, to know (someone) / (colloquial, in the negative) to care in the least about, to be concerned with,

belly

Alternative spelling of 物知り: a person with broad knowledge, a knowledgeable person

stem or continuative form of 知る (shiru) [godan]

abdomen / belly / stomach