Fish That Fall In Love, And Their Lessons

by | Blog, Articles, Breeding and Care, Saltwater Fish

Valentine’s Day may come and go, but in some parts of the ocean, researchers have found it’s alive and well all year round. From stunning displays of courtship to lifelong bonds, humans have long studied the mating rituals of animals for science reasons, but the parallels to our own lives aren’t lost on us. Plus, it’s hard not to root for lasting courtship – Even if it’s not our own.

While birds usually get all the attention when it comes to monogamous animal couples we love (March of the Penguins, anyone?!), fish that find each other and stick together – the fish equivalent of falling in love – are not to be missed. Plus, they offer us insightful lessons on behaviors that strengthen bonds, even if you’re not a fish.

1 French Angelfish

French Angelfish Pair

Easily displaying one of the strongest bonds among fish, French Angelfish form a pair when they reach adulthood and stay together for the remainder of their lives. The couple lives much the way a married human couple does: Working during the day to peruse for food and retiring to their caves and crevices at night. These areas are part of their territory, which they’ll staunchly defend together if challenged.

The French Angelfish couple spends about half their time entirely together, and will even “carousel” (spin round and round together) when reuniting after being apart for a time – Reminiscent of a dog spinning happily in circles with excitement. University of West Indies writers note this behavior increases and reestablishes the pair’s bond.

This couple tolerates no shenanigans: If a bachelor or bachelorette angelfish wanders into their territory, the pair will quickly drive them off.

Throughout their lifetime, they mate together between April and September, sending up to an astonishing 75,000 eggs into the ocean.

Angelfish Takeaway for Humans:

Staying a united front and being sweet to your partner can go a long, long way.

2 Australian White’s Seahorse

White's Seahorse

Seahorses have long held the imagination of land dwellers, and White’s Seahorse is no exception. This small, 6 inch creature lives in the waters near Sydney and stands out among its aquatic peers for the incredible, lifelong bonds formed by mating pairs. Similar to the French Angelfish, these seahorses are in it till death-do-us-part once paired.

What’s more, they have a built-in commitment to keeping the love alive: For 30-60 minutes every day, they perform a “courtship dance” in which they circle each other, change colors to mirror each other, and exchange dance floor moves. This courtship dance reinforces their bond. It’s hard not to wonder what human relationships (romantic or otherwise!) would be like if we did this every day.

Researchers from University of Technology Sydney’s Dr. David Gladstone and Dr. David Harasti, who studies White’s Seahorses, put it this way after studying the animals’ mating pairs over the course of their lifespans:

“At no stage during the study, did a male or female leave their current partner whilst their partner was still present at the study site, even when there were other single partners available.”

The only exception they observed was when, “…their previous..partner had disappeared from the study site and was not recorded again.”

In other words, these seahorses will only “remarry” if they lose a partner.

NOTE:    Currently endangered, White’s Seahorse has lost over 90% of its population due to habitat loss. Australian scientists are working to combat this by establishing underwater “seahorse hotels” to provide homes for these beloved little couples.

Seahorse Takeaway for Humans:

Setting aside daily time to focus exclusively on each other can strengthen a relationship bond.

3 Japanese White-Spotted Pufferfish

White-Spotted Puffer Fish Art

Back in 1995, divers discovered an anomaly off the coast of Japan: Underwater crop circles. Cue Stranger Things music. Mysterious theories abounded until researchers discovered in 2011 that a tiny, 5 inch long determined pufferfish was behind these large, stunning, complex circular creations in the sands. The reason? To attract his true love.

The white-spotted pufferfish male spends over a week working constantly on his creation, wriggling his small body in the sand and flapping his fins to form incredible geometric patterns in the sand. Meticulous in his effort, he shops around for decorations, adorning his creation with shells and other items he finds on the sea floor.

By the time he’s finished, it’s a masterpiece that’s over 16 times bigger than he is.

Females will then evaluate the geometric circle as part of her process to see if he’s an appropriate mate. Researchers are still working to understand this process, but they know that the design acts as a nest, and theorize she may be able to tell the size (and therefore health) of the male puffer based on the design.

Tiny but making the most of his talents, this little fish may be a hopeless romantic: He creates an entirely new structure when meeting a new partner.

Pufferfish Takeaway for Humans:

Art, effort, and finding ways to communicate are gifts that make an impression on a partner.

4 Spongicola Shrimp (Spongicola venustus)

Clear shrimp

This is technically a clear shrimp, but it looks similar to a spongicola (which are very difficult to photograph, because well, they’re inside the sponge!)

The ocean is a daunting enough place for humans, but if you’re only 2 inches long, you’ll really have to get creative to survive if you call the ocean home. Spongicolas take “old married couple” to a whole new level by trading their freedom for the safety of a friendly – but impossible to leave – sea sponge.

These little shrimp-like creatures form bonded pairs before they’re fully grown, and quickly move in to a carefully selected glass sponge (called Venus’s flower basket) where they live together indefinitely, keeping the sponge clean in exchange for their stay. The catch is, they can never leave. By the time they’re fully grown, they’re too big to fit through the sponge’s exit. So they stay, eat, live, and breed, releasing their tiny shrimps (who can fit through the exit) after breeding.

While this arrangement may be ripe for dark humor, it serves the important purpose of food and shelter for the pair, and the glass sponges themselves are frequently given as wedding gifts in Japanese culture, signifying the lifelong partnership.


Venus' Flower Basket

Photo of the glass sponge (Venus’ Flower Basket)

What’s more, the glass sponge the shrimp lovers choose is in itself remarkable; Called “Venus’ flower basket,” these glass sponge reefs were thought to have died out 40 million years ago, only to be rediscovered in 1987. These shrimp chose a home that was around during the time of the dinosaurs, which seems oddly fitting for their “ride-or-die” commitment.

The sponges themselves are currently being studied for its load-bearing capacity and light-transmitting fibers. Scientist and top researcher on the subject Dr. Joanna Aizenberg speculates these fiberoptics may help attract the shrimp to the sponge.

Shrimp Takeaways for Humans:

Old married couples have figured out how to make it work; Talk to them. But remember that leaving is an important human option, too.

Wrap Up

Monogamy in the animal world is hit-or-miss, but it’s rare when it comes to fish. Even then, definitions of monogamy can vary. Naysayers may reasonably cite the biological imperatives that animals have for staying together, from safety to scarcity of partners, but is it really such a far leap from our own? Humans have their own needs, and companionship counts.

The four sea creatures above are remarkable in their ability to forge truly monogamous, lifelong partnerships till death do us part – Literally. Considering only half of Americans are currently married, these fish may just have a thing or two to offer.



To say that I’m obsessed with all things saltwater is a bit of an understatement. Aquarium Passion has served freshwater and saltwater aquarium hobbyists for over 10 years, and I'm committed to keeping the information accurate and free. My post-bac certification in Sustainability informs my writing about aquarium conservation efforts. When I'm not writing at AP, I'm out in the ocean or researching weird fish.


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