Cockroaches are intruders that infiltrate homes and businesses through small openings, drain pipes, and even by hitching a ride on you. They are highly resilient and reproduce rapidly. They thrive in unsanitary conditions and spread germs and bacteria through their legs. Once they establish an infestation, over-the-counter solutions are usually ineffective. In Singapore, there are two types of cockroaches that are most commonly seen: American and German cockroaches. While German cockroaches are smaller, around 1-2 cm, American cockroaches are larger, with sizes between 4-5 cm.