KEY BISCAYNE, Fla. -

A 28-year-old man was rescued Monday morning after his boat capsized off Key Biscayne, forcing him to tread water for hours while his brother swam to shore to find help.

George Verdecia and his older brother went fishing about 7 p.m. Sunday, according to Vanessa Florido, Verdecia's girlfriend.

"He was supposed to be home at 2 and when I noticed he wasn't home is when I started worrying," said Florido.

Sometime during the fishing trip, the boat capsized about three miles off shore, according to the U.S. Coast Guard. Neither man was wearing a lifejacket when the boat capsized.

"The wake was too big and it basically capsized the boat. He said it happened so fast, he wasn't able to grab or do anything," said Florido.

"Seven hours is a very long time to tread water," said Coast Guard Lt. Cmdr. Joseph Abeyta. "So, again, the Coast Guard always wants to stress, you got to wear the lifejacket. That is the primary -- it's just like wearing your seatbelt in your car. You don't get in your car without your seatbelt, you really shouldn't get on-board without your lifejacket."

Verdecia was forced to tread water overnight and used a cooler to help him stay afloat.

"This is what saved his life," said Abeyta. "That man was physically exhausted and this was barely keeping him afloat."

Verdecia is usually a strong swimmer but has been suffering from back pain.

"He has really bad back problems and because of everything that happened. He must've pulled something but he says his back is hurting him right now," said Florido.

"Had he not had the cooler. Had he just had a little plastic bag with his stuff in it -- I'm not too confident that individual could've survived this morning," said Abeyta.

"The brother that was out in the ocean couldn't swim in. He was having some difficulty, so the other brother was able to swim to shore," said Osorio.

The older brother swam to shore to call for help.

Sky 10 helped rescuers find Verdecia on Monday morning.

"He was still treading water. The Coast Guard went up on him. We used Channel 10 media helicopter actually to help us locate him, and they spotted him. They were over him, hovering, and were able to help us locate where he is and guide the Coast Guard," said Key Biscayne Fire Department Dep. Chief Marco Osorio.

Both men were transported to Mercy Hospital and are expected to recover.

"He's fine. He's just really cold right now and the skin from being in the water too long. Dehydrated, but they're keeping him warm and they're giving him water and they're going to feed him something to what so he should be better," said Florido.

The men are expected to be held overnight for observation.