Tens of thousands of dead fish are washing up in Brevard County waters, and residents have sent us dozens of pictures.

The dead fish began turning up in the Indian River Lagoon over the weekend.

The Florida Fish and Wildlife Conservation Commission sent biologists to Brevard County to figure out what's going on with the brown tide. Past studies have shown a massive underwater algae bloom that is killing sea grass and soaking up oxygen, which gives fish nothing to breathe.

A rally will be held from 2 to 6 p.m. Saturday, March 26, at the intersection of State Road 520 and A1A. It's being called "Stand for our Lagoons."

To report fish kills, call Fish and Wildlife's fish kill hotline at 800-636-0511.