Major system crash-- no idea why

[Hypancistrus]

I came home from work today to find two of my most prized predators dead... my african brown knife, a 6" fish I've had for over three years, and my 5" pictus catfish, who I've had for slightly less than three years. The rest of my fish-- two severums, 5" a piece, a nandus, 4", a senegal bichir juvie, 4", and three silver dollars at 3-4" all look like death warmed over. The only one that seems unaffected is my African butterfly. I tested the water parameters. Ammonia and trites are at zero, and trates were around 50, which is normal for a Friday (water change day). Temp is stable 76 degrees as always. The tank is a 75 gallon, with plants.

I can't for the life of me figure out what the hell went wrong. All the fish were perfectly active and happy on Wednesday when I fed them their live blackworms and sinking pellets, and now two are dead and five others look about ready to join them.

I changed NOTHING in the tank, there are no marks on any of the fish, nor had I added any live food other than worms recently. I did a 40% water change, and am going to try another in about two hours.

What else can I do?? What went wrong? The only thing I can think is that last night I did two loads of laundry without realizing that the hose on my dryer had come partially detached. I only noticed it when I walked down into my basement (which is my combo fish and herp room) and the temp was way warmer than usual. This is the ONLY thing I can think of....

[Miguel]

I would wager a nitrate peak.

[fishboyakadean]

yea i would to

[Pyramid_Party]

check PH too

[Hypancistrus]

Nitrates are normally around 50 on Friday's. Have been for the three years I've had the tank running.

[nfored]

you said live black worms, could they have been infected with something?

50 isn't all that high, higher then I would like, but I challenge someone to find me 1 proof positive nitrate death when the trates where bellow 80.

pH with nitrates at a constent 50 is very good guess, trates form an acid which can drop pH over time. If your water is soft and you have had 50 trates for 3 years the pH might be very low.

[sammy5772]

Ive had a perfectly healthy angelfish in a tanks that had been running for a year die with nitrates at 40.

[cassharper]

hey hyp! Fancy seeing you round these parts.

I doubt it was nitrate poisoning, considering some keepers (see the nitrates thread) think it's ok to keep their tanks between 50-60 all the time.

If the room was a little warmer maybe a drop in O2 content?

[Cichlaholics Anonymous]

could be something from the live worms, what is their source?

[pdbrady]

Do you run carbon? Is there any chance something could have floated into the tank? Anything aerosol, like air freshener, for example. Maybe put a hand in the tank with something on it, like lotion. If so, and you don't run carbon, those are possibilities.

[nfored]

could be something from the live worms, what is their source?

::iagree::