Enables fumarate hydratase activity. Involved in fumarate metabolic process; malate metabolic process; and tricarboxylic acid cycle. Located in mitochondrion. Human ortholog(s) of this gene implicated in fumarase deficiency and lung non-small cell carcinoma. Orthologous to human FH (fumarate hydratase). [provided by Alliance of Genome Resources, Apr 2022]