However, the Delgados in Texas said Frankie didn't exhibit any symptoms until later at home when he started vomiting and had diarrhea.
Four-year-old Francisco Delgado filled his lungs with fluid while swimming and died the next day, KTRK reported.
Francisco III's heartbroken dad said: "Out of nowhere, he just woke up". "He took his last breath and I didn't know what to do no more".
Doctors say they found fluid in Frankie's lungs and around his heart.
Symptoms of dry drowning and secondary drowning may include coughing, chest pain, trouble breathing and feeling extremely exhausted. As of Wednesday evening, almost $14,000 has been raised for Frankie's family.
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Dr. Kay Leaming-Van Zandt said she was cautious to use the term "dry drowning", explaining that parents need to be aware of the dangers of drowning in even a few inches of water.
Little Frankie seemed to be getting better, just a fun-loving kid with an upset stomach.
"That's where you have the cardiac arrest, because you're not carrying enough oxygen", Fitz said.
Vega, the father of the surviving toddler, wanted Frankie's parents to know their son's tragedy helped to save another child. Six days later, he abruptly woke up during the night, took a deep breath and died, the apparent victim of a rare phenomenon often referred to as "dry drowning".
If you think someone is having these symptoms, go to the emergency room, "because time is of the essence when it comes to dry drowning", Higginbotham continued.
They account for about one to two percent of all drowning incidents.
Funeral services are scheduled for Saturday, May 10.