A fire Monday morning on Dodecanese Boulevard did an estimated $19,000 damage to a Sponge Docks gift shop and deep sea fishing service, according to Tarpon Springs Fire Rescue. No one was home in the third-floor apartment above the Dolphin Curio Shop at 810 Dodecanese Blvd. when the fire started at 6:45 a.m., Tarpon Springs fire Capt. John Merante said. He said an electrical malfunction in a hot water heater on the third floor started the fire, which spread quickly on the top floor of the building. No one was injured. More than a dozen firefighters from East Lake, Palm Harbor and Tarpon Springs worked for nearly 90 minutes to extinguish the fire. Locating the fire was difficult, and fire crews struggled to minimize damage to the gift shop and boat dock below, Merante said. He estimated that firefighters doused the blaze with 500 to 1,000 gallons of water. Damage from smoke and flames could add up to about $15,000 with water damage adding another $4,000, he said.