V Lionfish question

I have had no luck searching the net or asking questions to find the answer to this question. Do lionfish expell there posion when they die?? My tank was completly wiped out after he died and I have no clue why. All levels were good except alkalinity was high but had been where it was for weeks

 

AFAIK their toxin can kill anything in the tank... best to keep a lionfish in its own tank for this reason. as i understand it, even if they do attack something and it releases that toxin into the water it'll just kill anything that consumes the toxin-water

 

Thankyou