CATFISH (Collider grAviTational FIeld Simulator for black Holes) is a Fortran Monte Carlo program to simulate TeV black hole production at CERN’s Large Hadron Collider. The fundamental scale of gravity may be much lower than the measured gravitational scale. In scenarios with large or warped extra dimensions, the observed weakness of gravity is explained by assuming that standard model fields are constrained to propagate on a four-dimensional submanifold, whereas gravitons propagate in the higher-dimensional spacetime. If the gravitational coupling constant is of the order of few TeVs, super-Planckian events at CERN’s LHC could lead to the formation of subnuclear black holes and branes. The semiclassical Hawking effect provides a thermal decay mechanism for black holes, thus allowing their detection. Under the most favorable circumstances, the black hole event rate at the LHC should be comparable to the ttbar event rate. Until now, numerical studies of observational signatures have used Monte Carlo generators implementing the semiclassical picture outlined above. Currently, there are two generators for black hole production at particle colliders: TRUENOIR and CHARYBDIS. However, recent results have modified significantly our understanding of black hole formation and evolution. CATFISH deals with the observational signatures of black hole events beyond the simple semiclassical model by including many of the accepted theoretical results in the literature. The generator, called CATFISH, interfaces to the PYTHIA Monte Carlo fragmentation code. Generators with similar characteristics of CATFISH have already been successfully utilized to simulate black hole production in ultrahigh-energy cosmic ray air showers and in lepton colliders such as the muon collider.