After replacing the filter media with new ones, the fish died instead. Whose responsibility is it, really?

A fish keeper submitted a report saying, "Filter media are supposed to purify the water, but after putting filter media in the tank, the fish died instead. The filter media must be the problem. I suspect the heavy metals exceed the standard and caused an adverse reaction, but the seller refuses to deal with it for all sorts of reasons. It's so infuriating."

According to this fish keeper, he was introduced by a friend and began keeping stingrays for everyday viewing 2 years ago. "This is a round-shaped fish, a tropical fish species, an imported variety, and quite valuable; at the beginning, the ones I bought were all small fish, over 10 cm long. After two years of keeping them, the large ones have now grown to 35 or 36 cm long."

This kind of fish originally lived in the wild, is rather sensitive and has high water quality requirements, so during keeping, some aquatic plant filter media need to be added to purify the water. "Aquatic plant filter media are a kind of granular bacteria ball, mainly used to cultivate bacteria, decompose and remove harmful substances, and keep the tank water quality safe. I have used this kind of filter media many times before, and I also bought them at this shop, and there had never been a problem; 5 days ago, after the batch bought earlier ran out, I bought another batch." said Mr. Chen.

"The filter media used to cost 9 yuan per jin, this time it was 5 yuan per jin. At first I had some doubts, and the salesperson said it was a discount for regular customers." This fish keeper said. At about 2 p.m. that day, after returning home, he put the prepared filter media in after changing the water, as usual, to purify the water quality. "Just a short while after putting it in, I found something was wrong. 2 smaller stingrays reacted immediately; they had been swimming in the water, then suddenly lay on the bottom of the tank and did not want to move. When I turned on the circulation pump, the fish floated right at the water surface. At a glance, it was not normal."

After discovering this situation, the fish keeper immediately called the seller and explained what had happened. "After hearing the situation, the other party said the problem was not serious, that the PH value had fluctuated a bit, and that increasing the pump oxygenation would be enough. Of the 2 slightly smaller stingrays, one died on the spot. Although the seller said so, I was still a little uneasy, so I put the other one in another tank." The fish keeper said that because he had something to do that afternoon, he went out later, and when he came back he suddenly found that of 6 large stingrays, 4 had died. "I had raised them so painstakingly, and of 8 fish, 5 died. Based on the current market prices, the loss must be more than 5,000 yuan. It is so heartbreaking. This situation must have been caused by a problem with the filter media, but after communicating with the seller many times, they refused to deal with it for all sorts of reasons. It's so infuriating."

This fish keeper then contacted a newspaper reporter, hoping to expose this unscrupulous seller.

Seller: It was caused by the fish keeper himself, it is not our responsibility

The reporter contacted Manager Xu, the seller of the filter media. "I received the customer's report that evening, so I went over. There are many kinds of situations that can cause stingray deaths. Based on my judgment, this matter was caused by the fish keeper's lack of fish-keeping experience, and it is not our responsibility." Manager Xu said.

Manager Xu told the reporter that stingrays come from Brazil, belong to tropical fish, are relatively valuable varieties, and have fairly high market value, so keeping them is especially strict. "To keep fish, first keep the water. This is essential knowledge for tropical fish, and for keeping stingrays, the most important thing is water quality. Even a small change can cause them to overreact. Situations such as lack of oxygen, water quality deterioration, and sudden changes in water quality can all be causes of their death reactions." Manager Xu said that because many indicators of today's domestic water do not meet standards, these filter media need to be used to cultivate nitrifying bacteria and stabilize water quality.

"This fish keeper's situation belongs to improper operation, which caused ammonia poisoning in the stingrays." Manager Xu said that this customer's tank was an old tank. Because the fish eat, drink, and excrete in it, there is a lot of feces, and the ammonia nitrogen in the tank is relatively high. If the filter media were not replaced, the ammonia nitrogen would certainly exceed the standard. "According to the requirements, before replacing the filter media again, the tank should also be rinsed several times, but because when he changed the water, the filtered water was not drained cleanly, a reaction occurred. That evening, after receiving the report, I went over and dissected the dead fish, and found that these fish had problems in their intestines to begin with. If the filter media had not been replaced, it would have been somewhat better; once the filter media were replaced, the PH value in the water rose rapidly, causing the fish to be unable to stand it and die."

Manager Xu said that in order to test the quality of this batch of filter media, after discovering the situation, he did another experiment and put some of the customer's remaining filter media in his employee's fish tank, and found that the fish were completely fine. "Later, still uneasy, we did another test ourselves. We put the filter media in water for 2 to 3 hours, waited for the bacteria to be fully released, and then tested it, and found that the PH value and all other aspects met the standards, and there was no problem. The filter media we sell all come from legitimate manufacturers, and there is absolutely no problem with the quality. Regarding this situation, if the customer feels there is a problem, he can find a specialized institution to test it. If it is our problem, we will certainly take responsibility." Manager Xu said.

City Consumers Association: Responsibility must be divided after the filter media are appraised

On how to handle this matter, the reporter consulted the city Consumers Association, and its staff member said that if the two sides do not agree, this situation requires appraisal; without test proof, it is impossible to say there is a quality problem. "In this situation, it is recommended to go to a testing institution recognized by a legal body for testing. If it really cannot be tested, you can ask fishery experts to conduct an on-site inspection and ask the fishery department to issue a certificate, which can also have a certain effect. If testing shows there is a problem with the filter media, the seller and manufacturer must bear responsibility. If it was caused by other reasons, the seller and manufacturer have no direct responsibility; if mediation between the two sides fails, it can be resolved through legal procedures." the staff member said.

The editor thinks, each side says it is in the right. How do you all view this matter?