Fish story

Animal Planet devotes three hours to trying to convince you that mermaids exist. It’s unlikely “Mermaids: The Body Found” (7 p.m. Sunday, AP) and “Mermaids: The New Evidence” (9 p.m.) will make me a believer — unless scientists can prove these creatures look exactly like Daryl Hannah in “Splash.”

We salute you

Gary Sinise and Joe Mantegna once again preside over “The National Memorial Day Concert” (7 p.m. Sunday, TPT, Ch. 2), a tribute to real-life toughies. Special salutes will be made to veterans of the Korean War and Charles Durning, a World War II hero who died this past December.

A bug’s life

First they took over the East Coast; now they’re taking over our televisions. “Cicadas and Invaders 2013” (8 p.m. Sunday, Science) looks at how these bugs rise from the Earth every 17 years to give thousands of Americans a massive headache.

Neal Justin