one by one :(

[johnnyriker22]

That sucks that relatives put bleach in your tank. That's pretty stupid. I'm glad some of your inhabitants made it through. Have you de-chlorinated afterwards with prime or water conditioner?

You must have some major stress in your tank for this overnight death to be occurring. Try to stabilize everything in the tank like temperature and alkalinity. Don't let temperature fluctuate more than 2-3 degrees a day. See what your nitrates are like in the tank. Check out how to use active carbon properly. I use a cup every 2-4 weeks for 90 gallons of volume for example but every tank is different.

johnny