Fisher's father ultimately aided his entry into the navy, via his godmother Lady Horton, widow of the governor of Ceylon to whom William Fisher had been Aide-de-camp. She prevailed upon a neighbour, Admiral Sir William Parker (the last of Nelson's captains), to nominate John as a naval cadet. The entry examination consisted of writing out the Lord's Prayer and jumping naked over a chair. He formally entered the Royal Navy on 13 July 1854, aged 13, on board Nelson's former flagship, , at Portsmouth. On 29 July he joined , an old ship of the line. She was built of wood, in 1831, with 84 smooth-bore muzzle-loading guns arranged on two gun decks, and relied entirely on sail for propulsion. She had a crew of 700, and discipline was strictly enforced by the "hard-bitten Captain Stopford". Fisher fainted when he witnessed eight men being flogged on his first day.