Pesca is a program that helps in the construction of proofs in sequent calculus. It works both as a proof editor and as an automatic theorem prover. Proofs constructed in Pesca can both be seen on the terminal and printed into LaTeX files. The user of Pesca can choose among different versions of classical and intuitionistic proposition and predicate calculi, and extend them by systems of nonlogical axioms. The implementation of Pesca is written in the functional programming language Haskell.