At the Two Oceans Aquarium in Cape Town, some of the most remarkable stories happen behind the scenes. One of those stories is unfolding right now: A brand-new generation of Western clownfish has been successfully hatched and raised by the Aquarists at the Aquarium.
These tiny new arrivals are more than just adorable additions to the Aquarium. Their journey reflects the extraordinary care, patience and scientific expertise that goes into creating healthy marine environments and protecting ocean life for future generations.
The Aquarium’s clownfish breeding initiative began as an effort to strengthen the genetic diversity of their existing clownfish population by introducing clownfish parents, Finn and Skye.
Behind every successful hatch is a carefully recreated world designed to mirror the conditions clownfish rely on in the wild. For the Aquarists, that meant paying attention to every detail.
In Quarantine, Aquarist Abdulmuhaymien Malick and the team prepared a calm, stable environment inspired by the sheltered spaces clownfish naturally choose on coral reefs. Hatching clownfish requires paying attention to every small detail – these fish are highly sensitive to environmental changes, which makes breeding them a delicate process.
Water temperature was carefully maintained between 25 and 26ºC, salinity levels were closely monitored, and the pair’s holding chamber was placed in a quiet, low-traffic area to minimise stress. Automated lighting recreated a natural day-and-night cycle, helping Finn and Skye feel as though they were right at home on the reef.
Even their choice of nesting site reflected natural clownfish behaviour. Given a selection of surfaces, the pair chose unglazed tiles and terracotta pots – sturdy, flat options similar to the smooth rocks wild clownfish choose near their host anemones.
The breeding process itself was a fascinating example of instinct in action.
In the wild, clownfish breeding is closely linked to lunar cycles. Around the full moon, breeding pairs leave the safety of their anemone for the female to deposit hundreds to thousands of eggs on their chosen surface, which the male immediately fertilises and guards.
Finn and Skye displayed these same natural behaviours at the Aquarium. Once the eggs were laid, Finn took on the important role of caretaker, constantly cleaning the eggs and fanning them with his fins to keep oxygen-rich water flowing over them. Skye remained nearby, just as wild females do.
Rather than interfere, our Aquarists allowed this parenting process to unfold naturally. By working with the fish’s instincts instead of against them, the team gave the eggs the strongest possible start.
Supporting successful breeding also meant ensuring Finn and Skye received exceptional nutrition. In the wild, clownfish are opportunistic omnivores that feed on drifting zooplankton, algae, old anemone tentacles and other reef debris.
To mirror this varied diet, the pair were fed nutrient-rich meals up to four times a day, including ocean flake, hake roe and bloodworm. This helped keep the fish healthy and in peak breeding condition.
For the Aquarists, watching the eggs quickly became one of the most exciting parts of the process!
Clownfish eggs undergo visible changes as they grow, beginning as translucent yellow before gradually developing dark eye spots. Around day six, those eyes turn a reflective silver – a telltale sign that hatching is near.
Throughout this period, Finn continued tirelessly caring for the eggs, removing any damaged ones and keeping the healthy eggs clean and aerated. After about a week, the eggs were carefully transferred to a specialised hatching chamber where conditions could be even more closely controlled.
This stage also mirrors nature. In the ocean, clownfish parents do not raise young beyond the egg stage. Once hatched, larvae drift away with ocean currents before eventually settling on reefs of their own. To replicate these conditions, the Aquarium team ensured the hatching chamber remained calm and dark, as clownfish naturally hatch at night to avoid predators.
When the fry finally emerged, they were astonishingly small – even tinier than a pinky fingernail! From that moment on, Two Ocean’s Aquarists stepped into the role the ocean would normally play, carefully supporting the fry through their earliest and most vulnerable life stages.
For the first few days, the baby clownfish were fed live rotifers (microscopic organisms like zooplankton) three times daily. As the fry grew, they were gradually introduced to newly hatched artemia and later protein-rich foods like hake roe.
To sustain this delicate ecosystem, the water was lightly tinted green with phytoplankton, which fed the rotifers and artemia and ultimately supported the growing clownfish population. Every aspect of their care was designed to reflect the natural processes that occur in healthy marine environments.
Today, visitors to the Two Ocean Aquarium can admire these tiny new residents in the Diversity Gallery – a heartwarming reminder of the dedication and expertise that goes into caring for marine life.
The successful hatching of this new generation of Western clownfish is not only an exciting milestone for the Aquarium, but also a celebration of the ocean’s resilience and the power of thoughtful conversation.
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Picture: Supplied
