Aquapark Reda after the chemical incident. Sharks, permits and species protection

They arrived in Reda in the spring of 2016, before the waterpark had opened its doors, and for a decade they were the facility's signature. Blacktip reef sharks in a 330,000-litre tank, with a slide tunnel running straight through the middle, made for an attraction no other venue in Poland could match. On Sunday 26 July, following a chemical incident in the plant room, all twelve sharks died. The tank is now being refitted, and no decision has been announced on whether the animals will ever return. In the week since, the dispute around the case has grown larger than the incident itself.

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02 august 2026   |   15:09   |   Source: Gazeta Morska   |   Prepared by: Kamil Kusier   |   Print

fot. Albert Kok

A tank built to imitate a reef

The Reda aquarium was, and formally still is, one of the largest tanks of its kind in Poland. Four and a half metres deep, 330 cubic metres of water, an artificial reef and several hundred other fish. The installation simulated moon phases and times of day to bring the animals' circadian rhythm closer to the one they knew from the tropics. A glazed slide tunnel passed through the middle of the tank, and a dive pool with a transparent wall adjoined it on the other side.

At the opening in July 2016, Adam Mierzejewski, then director of the waterpark, spoke to reporters about fifteen sharks taking up residence in the aquarium. By July 2026 there were twelve in the tank, and all of them died as a result of the incident.

How they came to Reda

The animals appeared at the site long before it opened. By early May 2016, with construction still under way, the aquarium had been ready for several months and the water prepared for its future residents. Project manager Adam Mierzejewski said at the time that the sharks were flying in from Sri Lanka and Venezuela among other places. A month later, in June, the plan was reported as twenty sharks in total, with the first already settled in.

The group ended up smaller than announced. By the July 2016 opening the figure had become fifteen blacktip reef sharks, and only one point of origin was mentioned, Sri Lanka. That version stayed in the facility's information materials for the entire decade, although by the time of the incident the number was lower still.

One further point is worth adding. According to this newsroom's findings, the waterpark did not buy the sharks, it received them. That sounds like a detail, but it is not one. Behind every purchase of animals sits demand, and behind demand sit further removals from the wild. No such transaction took place here, so the creation of the Reda aquarium did not drive trade in the species. The same principle should apply if a decision is ever taken to restock the tank.

The work nobody saw

The sharks in Reda were talked about mainly as an attraction: the slide through the aquarium, diving alongside the glass, feedings in front of an audience. Behind that sat ordinary, laborious work that never features in attraction listings.

A good deal about it can be drawn from how the tank was described in its opening year. It was designed as a system in which almost every species has an assigned role. Around eight hundred other fish swam alongside the sharks at the time. Some of them, such as cleaner wrasses and juvenile bannerfish, remove skin parasites from larger fish, exactly as they would on a genuine reef. Others graze algae and keep the rockwork clean. The reef itself was built from natural dry rock shipped from Fiji, on the assumption that it would take a few years to become populated on its own. The stocking was chosen to limit conflict, since reef fish are aggressive by nature, and in a large tank with a numerous population that aggression spreads across many directions rather than concentrating on individual animals. Michał Snochowski, then director of the aquarium, described it as a whole meant to settle into balance by itself.

The routine was equally concrete. Daily cleaning of acrylic panels that scratch easily, siphoning the natural sand, removing algae from the walls and, above all, water changes, served by a separate 40 cubic metre reservoir. Seawater was prepared on site using a reverse osmosis filter and synthetic salt, holding parameters matching tropical waters, that is, incomparably more saline than the Baltic. Four people worked on the aquarium alone at the outset, with the team due to expand.

All of this has to be done every day for ten years, without breaks and without an audience, because from behind the glass only the result is visible. That is why one theme kept recurring in comments under the news of the animals' deaths: sympathy not only for the sharks, but for their keepers, whose decade of work was undone by a single mistake.

What is known about the incident

The event occurred on Sunday 26 July, shortly before 19:00, in the technical section of the building. According to the Pomeranian fire service, a technician unknowingly added sulphuric acid to a tank containing sodium hypochlorite, triggering a chemical reaction and the release of chlorine. Around 400 people were evacuated and one employee was taken to hospital.

In a statement issued on 30 July, the company's board indicated that rescue measures for the fish were undertaken once the emergency services granted permission to enter the aquarium, and that no such possibility existed while the operation was ongoing. This is a significant element of the chronology, and it explains why help reached the animals later than their keepers would have wanted. A full hour-by-hour timeline has still not been published.

The remaining animals at the site, including those in the Gadoland exhibit, are in good condition according to the company, with no signs of poisoning, and the situation was reviewed with the veterinarian responsible for their care.

Too much heat, too little of the back-of-house detail

A week on, the subject of public discussion is no longer the incident but the way it has been talked about. Company statements appeared and disappeared, the municipality suspended its cooperation with the facility under the resident card scheme, and successive social media posts raised the temperature on both sides. Lost in the noise was the thing that matters most in situations like this, namely the back-of-house work.

Because in a facility of this size everything comes down to three things that have to function at once.

The first is the safety of people on site, including staff in the plant room. That is where the event occurred and where someone was genuinely harmed, with one employee hospitalised with symptoms of poisoning.

The second is the safety of guests using the attractions: the quality and parameters of the pool water, the performance of the treatment system and evacuation procedures. On the day, the evacuation of around 400 people passed without casualties, and the company maintains consistently that the water in the pools was never at risk.

The third is animal welfare: daily monitoring of tank parameters, observation, and safeguards against events in parts of the building that do not directly adjoin the aquarium. This is precisely what the audit of technical systems and procedures announced by the company addresses.

To these a fourth component must be added, without which the first three cannot work: accurate and prompt information. This is not about the tone of statements or who answered whom more sharply, but about facts reaching residents, guests and emergency services at the same time and in the same version.

The questions that remain open in this case are mostly technical. How much time passed before the services allowed people into the aquarium, how the chemical installation was safeguarded, and what the ongoing audit will change. The answers determine whether a similar situation can recur, and they should be the axis of the conversation.

Why rebuilding the tank takes time

Replacing the water is the simplest part of the exercise, though even that means tonnes of salt at 330,000 litres of artificial seawater. The harder part is what cannot be seen from behind the glass.

Chlorine is lethal to fish at trace concentrations, but it also destroys the bacterial colonies in biological filtration, the invisible engine of any large aquarium. These process nitrogen compounds and keep the tank in balance. Rebuilding that microflora is not a matter of decisions or money but of time, usually measured in weeks. Add to that cleaning the artificial reef structure, verifying the installation, and only then gradual restocking, preceded by quarantine. A refit announced without a completion date is therefore not necessarily evasion. In this field, declaring a date before parameters have been re-established would be recklessness rather than transparency.

One point tends to get lost in the commentary. There was no ill will behind the incident. There was a routine task in the plant room, performed hundreds of times, and a single error about which tank was which, releasing chlorine. The employee who made it ended up in hospital himself. This is the human factor in its classic form: not recklessness, not neglect by the animal keepers, but bad luck at a point where procedures and safeguards should catch an error before it grows. And that, rather than the people, is where the conclusions belong, because in any facility of this size someone will eventually reach for the wrong container.

Where else the species can be seen in Poland

Reda was not the only place in the country with blacktips, though it was the most spectacular.

The largest group today is at Wrocław zoo. In July 2026 the Afrykarium held seventeen sharks of three species: seven blacktip reef sharks, six sandbar sharks and four tawny nurse sharks. According to Jakub Kordas, the zoo's breeding director, the blacktips there measure around 100 to 120 centimetres, while the largest animals are female sandbars exceeding two metres and weighing several dozen kilograms. The nurse sharks are a bottom-dwelling species, placid, spending most of their time on the substrate.

The Wrocław animals share the Mozambique Channel tank with rays, a turtle and other fish, and are viewed from an eighteen-metre acrylic tunnel. Most of the sharks have names, and keepers use crib sheets to tell individuals apart. Public feedings, held Monday to Saturday, are combined with medical training: the fish learn to swim up to a keeper and hold position on a stretcher, allowing their health to be checked without causing stress.

In Gdynia the species arrived earliest. Two juvenile blacktips of around 60 centimetres came from Indonesia to the Gdynia Aquarium, a facility of the National Marine Fisheries Research Institute holding zoo status, in 2009, going on display after quarantine. Acquiring the animals and equipping the tank was made possible through the institute's cooperation with the Baltic Container Terminal. Today the species is kept in Gdynia mainly in the breeding facilities and shown on display periodically, including during Shark Week.

Blacktips have also gone to Warsaw zoo and are presented at the Orientarium in Łódź. Worldwide the species is among the most commonly kept in public aquariums, largely because it is smaller than most large requiem sharks and copes better with tank conditions. The same qualities that make it a rewarding aquarium resident make it an easy target in the wild.

A species under pressure, but with no reintroduction programme

The blacktip reef shark is classified as Vulnerable on the IUCN Red List. The 2020 assessment downgraded its status from Near Threatened and rests on an estimated global population decline of 30 to 49 percent over three generations, calculated at around 44 years.

The reason losses recover so slowly lies in the species' biology. It is a viviparous shark of low fecundity: a female typically gives birth to two to four pups, and gestation can last sixteen months. Add to that bycatch in industrial and coastal fisheries, the taking of fins, meat, skin and liver oil, and the degradation of the coral reefs on which this species strictly depends.

Here a point deserves to be stated plainly, because it tends to be blurred in debates about aquariums. There is no programme returning captive-bred blacktip reef sharks to the wild. Animals in public aquariums are not a reserve from which reefs are replenished.

Programmes of that kind do exist, but they concern other species. The most advanced is the StAR Project, launched in 2020 under the ReShark initiative, run in the protected waters of Raja Ampat in Indonesia and focused on the Indo-Pacific leopard shark, classified as Endangered. Eggs come from accredited breeding institutions in the United States and Australia, and the young hatch and grow in coastal nurseries run by local teams. The undertaking is backed by Re:wild together with the IUCN shark specialist group, Conservation International and the zoo and aquarium association, with over a hundred institutions from twenty countries taking part. Comparable work on a smaller scale is carried out by, among others, an aquarium in Malta, which recovers shark eggs from fish sold at market, rears the young and releases them into the Mediterranean.

The conclusion is therefore double-edged and comfortable for neither side of the aquarium debate. Keeping sharks in public aquariums does not protect this particular species in the wild and should not be presented as doing so. But breeding infrastructure and aquarists' expertise have proved, for other species, to be a real conservation tool that did not exist a decade ago.

What Reda owes the waterpark

It is worth stepping outside the aquarium for a moment, because without that context it is hard to understand why this case provoked such feeling in the town.

Before the waterpark was built, Reda existed in most people's minds as a place you drive through. A point on the road to Wejherowo, a dormitory town for Gdynia, or the stretch where the summer weekend queue to the Hel Peninsula begins. A town with no beach of its own, no old quarter, no attraction that would make anyone turn off the road.

The facility on Morska street changed that. Reda gained an attraction with no equivalent in the country, and it began drawing people into the town rather than merely past it. The waterpark became an employer, a destination for school trips from across Pomerania, and the entry that appears above everything else in searches for Reda.

The scale of that traffic is striking. The waterpark takes an average of 250,000 to 300,000 guests per quarter, giving one million to 1.2 million visits a year. At peak season the facility handles as many as three thousand people a day. Across ten years of operation that puts the order of magnitude at ten million visits, though a share of those are returning guests, so the number of individual people is lower.

For comparison, Reda has around 27,000 residents. The waterpark's annual footfall is therefore several dozen times the population of the entire town. Add that this is a year-round facility, with a hotel wing, saunas, a sports pool and a swimming school, so it draws people outside the season as well. For a town of this size that is not an addition to the offer but its backbone.

Which is why the dispute that played out over the past week on social media reaches beyond resident cards. The town and the facility need each other more than the tone of their mutual statements would suggest.

What happens to the aquarium

The waterpark has returned to normal operation and the aquarium is being refitted. No completion date has been given, nor any indication of what form that part of the facility will take. The operator has neither confirmed nor ruled out that sharks will one day return to Reda.

The question is not purely technical. Keeping large marine animals in entertainment facilities drew controversy in Reda even before the waterpark opened, and it is back today in national debate. The legal environment has also changed. Since 25 November 2023 the entire requiem shark family, which includes the blacktip reef shark, has been listed in Appendix II of CITES. Bringing the species under that regime means every international transaction, live animals included, requires permits and findings that the specimens were legally acquired and that the trade is not detrimental to the wild population. Reconstituting the group would therefore not be a simple repeat of what was done in 2016, when the species was not yet subject to that regime.

There is, however, a condition that should precede any other decision. If sharks were ever to return to Reda, it should be exclusively as animals transferred from another institution, captive-bred, or requiring relocation for husbandry reasons, and never as a fresh purchase and a fresh transport from the wild. That would, incidentally, be a repeat of what was done a decade ago. Taking animals from another facility does not increase pressure on the wild population, and for the animals themselves it is sometimes the better outcome, since institutions regularly move individuals between them when a group grows too large or animals need separating.

Practice shows this is not theory. Blacktip reef sharks reproduce under managed care, and the Gdynia Aquarium has noted that the species is also capable of parthenogenesis. The material to stock a tank without drawing on the wild population simply exists. The question is whether anyone will expect that of the facility, or whether the decision will be made purely in terms of timing and cost.

What cannot be predicted, and what can

One final point, which no piece on this case should omit, regardless of whose interests it serves.

An incident of this kind cannot be predicted. You can write procedures, duplicate safeguards and train people, and there still remains the moment when someone in a plant room reaches for the wrong container. That is how the human factor works, and it will work that way in every facility of this size, in Reda and anywhere else.

What can be predicted is that the factor will sooner or later come into play. And that is exactly what installations are prepared for: tank labelling, access procedures, isolation systems. The point is to stop a single error from growing to the scale of an entire facility. This is where the most important lesson from the Reda incident lies, and this is where the company's work is now directed.

But the human factor did not fail only in the plant room. It failed again afterwards, once the case moved to social media and emotion took over on both sides. Disappearing statements and barbs exchanged in public helped nobody: not the facility, not the town, and not residents who spent a week learning contradictory things. That part was not inevitable. It was a choice, and one made separately by each side.

One thing remains beyond dispute. For ten years Reda was home to animals nobody here had seen before, and the people who looked after them did it well enough that the sharks reached July 2026 in good health. What took them was not disease and not neglect by their keepers, but a few seconds at the wrong tank. For the facility this is a reputational and financial loss, for the town an inconvenience, but for the people who walked down to that aquarium every day for a decade it is simply a blow. And no audit and no statement will make that up to them.

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