Ralph Martell shows off a machaca he caught in Lago de Cote outside Nuevo Arenal, Costa Rica. (Nevin Martell/For The Washington Post)

“It wasn’t like this the last time I was here,” my father harrumphed as we cast our lines toward the shallows of Lake Arenal.

It was easy to believe him. We’d been fishing for more than two hours and there’d been nary a nibble. He had visited this lake in the northern reaches of Costa Rica nearly two decades earlier. His fond memories of bringing up more than his fair share of guapote, a cichlid fish with hypnotic spotting, and razor-toothed machaca had become one of his favorite tales to tell at family get-togethers, cocktail parties and anywhere else he could find an audience.

Details: Nuevo Arenal, Costa Rica

I didn’t mind that we hadn’t caught dinner yet. It was a sunny morning in early November of last year. A few wispy clouds punctuated the blue sky, and a slight breeze ruffled the lake, keeping us cool. At the far southeastern end, a wall of mist obscured Arenal Volcano, an active peak that had experienced its last major eruption in 1998.

I wasn’t sure that my father and I would ever have another day quite like this one. Although he’s the most active and adventurous 86-year-old I know, his hearing and eyesight have been slowly deteriorating in recent years, and he often gets dizzy spells — aftershocks from a decade-old stroke. Back home in Washington, my wife was eight months pregnant. Soon my responsibilities and schedule would change, making long trips like this one difficult.

“Let’s try trolling,” our guide, Sancho, suggested as he fired up the outboard motor at the end of his flat-bottomed johnboat.

He guided us away from the water’s edge until we were 100 yards out, then angled us parallel to the jungle-covered shoreline. As we cast our lines on opposite sides, I mentally crossed my fingers in the hope that we would catch something. I didn’t want this new adventure to end in disappointment for my father, who clearly wanted to add some new myths to his storytelling arsenal.

“I’ve got something!” I heard him exclaim behind me. Unfortunately, when he pulled in his line, he found an immature, six-inch machaca wriggling at the end of it.

Thankfully, his next strikes yielded a pair of two-pound fish that were tossed into an ice chest after a few quick smacks to the head. After another hour, I managed to add another to our haul. It wasn’t enough to brag about, but it would be enough for dinner.

We arranged for the fish to be prepared at El Establo (The Stable), a rustic roadside restaurant and horse-rental operation just outside the nearby town of Nuevo Arenal and a 10-minute drive from the villa we were renting. We were the only diners that evening, so we took over a long table near the open kitchen. The fish were washed, battered and fried whole. They arrived on a plastic platter with a simple salad of lettuce leaves, tomato rounds and cucumbers. The crisp salted skin paired well with the mild sweet meat, all washed down with rum-and-Cokes. It was a great meal, but it clearly didn’t measure up to what my father had been expecting.

The next morning, his disillusionment was evident during breakfast at Tom’s Pan German Bakery, a touristy but tasty outpost on the eastern edge of Nuevo Arenal, a tiny frontier-style town of just a little more than 2,000 residents. As we tucked into platters of fresh fruit and a basket of still warm whole-wheat breads studded with seeds and grains, he griped through reminiscence.

“Twenty years ago, we were pulling fish out of the lake that were this big,” he said, putting down his latte and holding his hands two feet apart. “We were throwing them back by the end of the day.”

I nodded gamely, trying not to become frustrated with his comparison with a seemingly impossible-to-top experience. I realized in that moment that I, too, wanted to be able to talk about this trip in such legendary terms.

When I was young I operated, like many children, under the wonderfully naive assumption that everything and everyone I knew would always be a part of my life. Growing older, watching family and friends slip off into the ether, has taught me otherwise.

As my time with my father inexorably shrinks, I cling ever more fiercely to the moments that we have together. The child in me thinks that if I hold on hard enough, maybe nothing will ever change. Listening to him live in the past made me feel as if he was ignoring the present. How could we have a new adventure together if he kept reliving the old ones?

After breakfast, he mentioned his dissatisfaction to our landlord, Glenn McBride, who had arranged our fishing expedition.

“You could always try Lago de Cote,” Glenn mused, “but only locals go there.”

That was all my father needed to hear. If there’s one thing he craves on vacations, it’s an authentic experience.

After Dad automatically agreed to the idea, I asked Glenn to give us a little more background. Just to the northwest of Nuevo Arenal, the heart-shaped lake is sunk into the center of an extinct volcano, he told us. The guapote and machaca are plentiful, and Glenn knew just the guide to take us — Jim Harvey.

Unfortunately, Jim could only take us on the day before we were due to leave. If we didn’t catch anything then, I knew that I was going to hear about it on the plane ride home (and every time our trip came up in conversation). Worse still, we weren’t going to have the adventure that we were both seeking.

When we woke early that morning, rain was lashing against the windows, a thick blanket of mist clung to the jungle, and the temperature was cold enough to require long sleeves and pants.

“I hope we can still go,” my father said as we nursed steaming cups of rich Costa Rican coffee sweetened with dark cane sugar. “I’d hate to have come all this way for nothing.”

A short while later, we were standing in Jim Harvey’s slate-paved living room. In front of the fireplace stood an artificial Christmas tree covered in lights and sentimental decorations that recalled a snowier holiday season. Jim himself sported a gray-and-white goatee, well-worn hands and a sun-wrinkled face.

“This is nothing,” he told us when I worried aloud that the weather would scuttle our plans. “We’ll catch a lot.”

When I inquired why more people didn’t go to Lago de Cote if the fishing was so good, he gestured toward a black-and-white aerial photograph hanging on the wall.

“Most people come here because of the flying saucer,” he said.

Taken in 1971 by a mapping crew from the Costa Rican National Geographic Institute at 10,000 feet, the picture clearly captures a slightly peaked disk hovering above the lake. UFO enthusiasts continue to debate its validity online and frequently make pilgrimages to the lake in hopes of making further sightings. Neither Jim nor his wife, Debra, had ever seen anything out of the ordinary, other than the ufologists who occasionally showed up unannounced.

After hitching his small boat to the back of his battered Land Rover, we rumbled down the muddy road, which was often just water-filled tire ruts running side by side, to the lake. The scene reinforced my growing sense that we were on the set of “The X-Files.” There was no defined shoreline; instead the edge of the lake indiscriminately flooded the fields and forests surrounding it. Trees devoured by the advancing waters jutted out of the dark lake like hands grasping in supplication.

The fog was so thick that you couldn’t see the far side, even though the lake is only about two-thirds of a mile wide and covers just under 1.25 square miles. As the boat chugged across the white-tipped waters, we huddled beneath its meager awning to avoid the worst of the rain. To help ward off the damp, Jim poured us shots of guaro, a slightly sweet Costa Rican liquor distilled from sugar cane juice.

On the far side of the lake, near a pair of giant sunken trees, we let our lured lines fly for the first time. Given the depressing weather and the surreal surroundings, my hopes weren’t high. The boat hadn’t glided 20 feet, however, before my father’s pole bowed toward the water.

“It’s a hit!” he yelled as he reeled in. This time, there wasn’t a throwback on the end, but a three-pound machaca. Minutes later, he was repeating his performance. He made it a hat trick within the first half-hour. Holding up his third catch, he flashed a smile that took decades off his face.

Despite the foul weather, he took a seat up at the exposed front of the boat. Bundled up in a salamander orange windbreaker, tan rain pants and a long-billed hat with a back flap to keep the nonexistent sunshine off his neck, he stood out against the dreamlike surroundings.

A moment later he was triumphantly crowing, “Another one!”

I wasn’t doing too badly either, having pulled up a pair of decent-size machaca. We would feast tonight.

I could already imagine the stories he was going to tell about this expedition. Our catch would be multiplied, the bad weather amplified and the oddity of our surroundings exaggerated.

And I would never contradict his version of events, even though, for me, the simple fact that we were spending time together was the perfect story.

Martell is the co-author of “The Founding Farmers Cookbook” (Andrews McMeel, October) and can be found on Twitter at @nevinmartell.