Born in 1962 in Managua, Nicaragua, Decasa began to paint in 1980 after working in the National Literacy Campaign. During this time, he entered the Primitivistic Painters group in Sutiava.

His painting style mainly reflects the religious customs, daily life in the countryside, the labors of artisans in the city, and the beauty of the landscapes of his homeland.

Decasa has participated in exhibitions in England and Norway, as well as in the United States. After participating in group exhibitions in Leon and Managaua, Nicaragua, Decasa received honorable mention in the Ruben Dario national arts competition.