Ms. Yang's mother, who lives in Hong Kong, bought cuttlefish at a market in Sham Shui Po, and a wild baby crab was mixed into the packaging bag. The elderly woman did not notice it and cooked it together with the seafood, intending to save it for her daughter who loves crabs.

When dinner time came, Ms. Yang noticed this crab with an unfamiliar appearance: its shell was red and covered with red spots. Being very familiar with various edible crabs, she had never seen this species before. She took a photo using her phone's AI image recognition tool, and the result was alarming — it was a red-spotted fighting crab, which contains a high concentration of tetrodotoxin.

The toxin in red-spotted fighting crabs is a potent neurotoxin that cannot be destroyed by high-temperature steaming or stir-frying. There is no specific antidote, and even a small amount can cause death. Considering that the crab's juice had contaminated the entire dish of cuttlefish during the cooking process, posing a risk of cross-contamination, Ms. Yang did not take any chances and threw away the whole dish. She also thoroughly cleaned and disinfected all the utensils, thus avoiding a poisoning incident for her family.

These marine creatures are also "toxic," hard to distinguish with the naked eye

According to reports, cuttlefish and other small fish caught near the coast often contain wild crabs from rocky areas. These toxic crabs have colorful patterns on their shells, appear fresh without any bad smell, and ordinary consumers find it difficult to tell if they are poisonous or not with the naked eye.

According to CCTV's science popularization, besides the red-spotted fighting crab, there are several other marine creatures that are also toxic: the upright clean crab is mainly found in Guangdong and Hainan provinces, and contains tetrodotoxin; the copper casted mature crab contains paralytic toxins, and the symptoms of poisoning include numbness of lips and hands, unsteady gait; the textile snail accumulates tetrodotoxin by feeding on toxic algae, which cannot be removed by cooking, and there is currently no specific antidote; the chicken heart cone has a toxic tooth at its tip, which can shoot out a lethal poison; the blue-ringed octopus shows bright blue or purple ring-shaped patterns when startled, and its venom contains tetrodotoxin, which is 1000 times more toxic than cyanide.