Major die off - need ideas

[shw104]

I had a major die-off in my tank this week… I have a planted, community tank, 30 gallon. It was up and running with no problems for well over 3 years. Last week, one morning I woke up and approx. ½ of my fish were dead. It appeared the remaining had a fungal infection of some type.. I did a major water change 50%, and treated the infection. The fish appeared to get better, did another 50% water change a few days ago.. last night, all the remaining fish looked healthy but woke up this morning and the remaining were dead.

Water looks clear, algae is under control (minor), temperature is fine, all normal water parameters (ph, nitrates) are within normal values. Plants are doing fine.

Any ideas??? I’ve had tanks for well over 20 years and never had a die off like this.

I’m really pissed as I had two large anglefish that didn’t make it. The remaining of the fish were tetras, zebras, neon’s, etc.

Any ideas?? What is the best course to bring this tank back? I’m a bit hesitant to add new fish.

I’m thinking I do a couple major water changes, let the tank settle for a bit and then add some feeder guppys and a gold fish. If they survive, then I’ll start adding other fish…

Thanks!!!
Scott

 

[bettabrat]

Did you do a WC and forget dechlorinator? Introduce any new fish? Are all these fish around the same "age"? What about change food brands or something? Have any pesticides sprayed around your property? What are your water params?

 

[shw104]

No new fish, yes used a dechlorinator (but had that though also).. perhaps something was off on my tap water.. though the fish showed signs of a fungus infection...

all fish were in the tank for at least 4 months.. most longer..

no changes in food and no pesticides that I know of. ..

 

[JAY973]

Is your tap city or well? Are you using Co2? Heater and filters working with out a problem?

I believe I've been affected by changes in the city water leading to fish loss myself. I love those pamphlets they send months later notifying you they changed something. It's R/O water for me.

 

[shw104]

city water.. but the city comes from either a reservoir or well... heater and filters are working well (or seem to be).. heater is fine.. first thing i checked as I had a heater go bad once before and my fish got cooked...

not using Co2.