Family left in terror after they spotted alarming detail in background of beach photo

A family was left terrified after noticing a chilling detail in the background of a beach photo.

Last year, SES Chelsea Unit took to Facebook to share a seemingly innocent photo taken at Carrum Beach in Melbourne, Australia.

The snap shows a typical beach day out: a father and his daughter waving at the camera, a dog enjoying the water, two men standing a bit further out in the sea, and another parent with a child nearby.

But upon deeper inspection, the eagle-eyed family noticed a harrowing detail in the background.

SES Chelsea Unit circled what seemed to be a shark fin not far from all the people at the sea.

The unit wrote in the caption: "As many of you would be aware, yesterday, we posted about a shark sighting, just off the beach, between Bonbeach and Chelsea. Well later, we received a message from a family, who follow our page, who were at Carrum Beach, earlier in the morning.

"It was their little one's first visit to the beach, and the gentleman’s partner grabbed a couple of snaps to record the day," they continued. "Later, when they got home and looked at the pictures, they noticed something in the shallow water, just behind them, was this our shark?"

The unit shared that when they viewed the photo, they weren't "sure" what the sighting was so they reached out to several places for their opinions.

"They all agree that although they can’t confirm it’s a shark, they can’t say that it’s not," the post reads. "So, what do you think?"

"The family are very genuine, and in fairness, they’re the first to admit that they’re not sure what they snapped, but they certainly would like to know. So if anyone has any genuine ideas of what it might be, please let us know," they concluded the post.

The family suspects that there was a shark in the background of their picture. Credit: Chase Dekker Wild-Life Images / Getty

Many people were left divided over whether the shape was a shark's fin or not, so they shared their suggestions in the comment section.

"There is a dog in the water near whatever it is so IF the dog didn’t get taken then that is not a shark. Dogs are the first thing to get taken. I’m thinking maybe more likely a rays flap, that would also account for the NO WAKE, and the dark shadow to its right could be its other flap," one person noted.

Another questioned if it was "a dolphin or a sting ray," adding: "They come fairly close to the shore. Jesus though… not keen to take the whippet for a swim now."

A third user shared a lengthy suggestion, penning: "Let’s say it’s a 20cm dorsal fin, for size percent based on bronze whaler that’s only a 1.5 - 1.8m shark. If it’s a 30cm dorsal that’s a 2.3 - 2.6m shark which on one that big would be a belly to bottom of dorsal height of about 45cm swimming in 60cm of water."

A fin appeared to be visible in the water. Credit: Philip Waller/Getty Images

"So a 1.8m shark of that species with a fairly slender belly could easily go unnoticed and would have been far too small to take a German Shepard let alone a person," they added.

However, a fourth chimed in: "A dog … it’s a dog..Ps banjo sharks are not actual sharks, they are a Ray."

Nevertheless, one more person simply said that regardless of what it is, it's "better to be safe than sorry".

What do you guys think?

Featured image credit: AL Hedderly / Getty