A video from a Sarasota diver shows schools of fish 10 miles from Charlotte Harbor, where toxic algae killed generations of sea life.

Schools of thousands of glittering fish can be seen swimming at reefs offshore from Charlotte and Lee County, in the area where decaying mats of vegetative debris and dying fish could be found during the peak of the Florida red tide bloom last year.

Sarasota diver Brian Dombrowski made two dives at Boxcar reef and one dive at Charlotte's reef July 19. He posted the video on Facebook to show people the condition of the reef.

Read more: Complete coverage of red tide in Southwest Florida

"The plants are coming back and fish had moved in," said Dombrowski of the Charlotte reef, believed to be the hardest hit area during 18 red tide months from October 2017 to February 2019. "You can see in the videos and photos possibly more so ... the plants around that starfish.

"We did not expect to see that level of active sea-life on Charlotte's as we did. It was a nice surprise."

The Florida Fish and Wildlife Conservation Commission attributed 589 sea turtles and 230 manatee deaths to the recent episode of red tide. It had killed 177 bottlenose dolphins as of Dec. 20, leading the National Oceanic and Atmospheric Administration to declare an unusual mortality event.

The artificial reef seen in the video is located 10 miles beyond Charlotte Harbor in 50 feet of water is made of lime stone rock and concrete slabs. It was deployed about 12 years ago.

Dombrowski said he is involved with the artificial reef programs in Charlotte and Lee counties, considered some of the top programs in the state, he said. Their most famous reef deployment was the USS Mohawk in July 2012 near Lee County.

"In that video there are schooling grunts, grey angelfish, hogfish, triggerfish, starfish, various baitfish," he said.

The last Florida red tide event subsided in February. There have been background traces of the toxic algae, which occurs naturally in the Gulf of Mexico, on the west Florida coast, but none of it has been at bloom conditions, according to Florida Fish and Wildlife Conservation Commission. They provide red tide status updates online at myfwc.com/research/redtide/statewide.

The latest report said that background concentrations of red tide were found in Sarasota County — those are considered typical conditions.

This story originally published to heraldtribune.com, and was shared to other Florida newspapers in the GateHouse Media network.