I went out to feed my fish the other day and all three of my catfish were dead. I bought these three little guys on the same day when they were only 3-4 inches long and when they passed were 8-12 inches each. About a day or two before they died I was adding water to the sump tank and forgot about it. I came back four hours later to a giant mess! The fish tank seemed okay, even my sump tank Plecos stayed put in the tank. I added water from the hose with a hose filter attachment. The manufacturer for the hose filter states it can filter up to 10,000 gallons of water and I had already been using this for a couple months. I tested my levels and everything was at 0. My tomato plants even drastically slowed their production since the incident.
Ammonia-0 Nitrite-0 Nitrate-0
If Chlorine did get into the tank and kill the microorganisms could that have killed the Catfish and left all other fish alive? Should I expect to lose more fish? Does it take just as long to restart a tank as it does to start a new tank?
Any help is greatly appreciated, thank you!!