Katie Stevenson, her husband Mark and three of her four children were rushed to hospital by paramedics wearing protective masks after cleaning the coral in their fish tank made it give off palytoxin, the second deadliest poison known to man.
Police and the fire brigade had to cordon off their home near Victoria Park at just after midnight last Tuesday.
Katie, 34, said if they had decided to go to sleep instead of calling 111 when the symptoms began, they would have died.
It is believed to be one of only a few recorded cases of palytoxin poisoning within the UK.
The adults, who were first hit by the toxins, were in hospital for about a week. Katie's three girls, who were asleep, were discharged the day after.
"All sorts of things were going through my mind," Katie said.
"My kids could have died. We could have died. I've not slept properly since.
"We had gone on holiday and our fish had died, so we decided to get rid of the tank. We completely emptied the tank and started scrubbing it. When you scrub it, it lets off toxins. The house had to be completely cordoned off by the police and fire brigade.
"About 10 minutes after cleaning the tank, I started to get a really dry cough. I said to Mark 'I have a sore throat coming', he said the same thing. We left it an hour, and I started getting really bad shivers. My temperature went up to 42 Celsius. We called 111 and they sent an ambulance.
"It was terrifying. The paramedics who came to get me were wearing masks. The whole A&E was isolated. They told us if we'd gone to sleep, we wouldn't have woken up."
Today the family has called for more to be done to make people aware of the dangers of having the common coral in their homes.
“We bought the coral and didn’t have a clue – they don’t give you any danger leaflets or anything like that," Katie added.
"You should be told about the toxins so you can know what you’re touching and how to clean it.
“We’ve had this fish tank for 12 months and always kept the coral underwater.”
Katie’s mother, Tina, arrived at their Victoria Park home to help after Katie had been taken to hospital. She said they were still in shock.
“When I arrived at their home I could taste it,” Tina said. “I could feel it in the back of my throat. My eyes were streaming.
“The fire service turned up and took the keys off me. They said I wasn’t allowed back in the house.
“When we got to A&E, they made us wait until they could be isolated. When they brought Katie to see us, I had never felt temperature like it. You couldn’t even touch her.”
The family is now on the mend, although they are being checked regularly by doctors.
Tina said: “There’s a lot of people out there with marine fish tanks. My family could have all died.”