so this morning when i got home i go to turn on my tank lights, and to my dismay i find more than half of my friends dead. both of my plecos, all 3 of my koi one of my orandas, and all four of my African clawed frogs, weird mix i know but that is besides the point. the survivors were 2 shubunkins one of my orandas and my black moor. The fish were fine in the morning when i fed them , active and hungry as they always are and i have not introduced anything new into their diet, they were also fine about 4 in the afternoon when i cam home from work although i did not take a good look at them, my room mate said they looked fine when she turned the lights off at night. but ant 9am this morning when i returned home they were not. although i have herd about this happening before to other people i never thought it would happen to me, tank has now been set up for almost a year i have had no big problems before, i did have a small fungus issue with the black moor when i first got him, but that has been the only thing i have had no fish die on me before this and everyone seemed healthy and growing as the should especially the frogs and the koi, i was actually in the process of finding them a new home as the were rapidly about to out grow my tank . Even though i am confused at the high death tole in the period of one night the death of the frogs confuses me the most. being that the frogs are not constantly taking in water as the fish are since they breath air from the surface. i took the survivors and placed them in my small quarantine tank for the time being. did a 100% water change changed the media in both my filters and refilled my tank. when i was butting everything back together i noticed a small crack in my heater, could that have something to do with it? the four remaining fish are still in quarantine untill i get everything figured out but does anyone have any clue to what might have happend overnight 8hours at the most to kill so many fish?

-andrew

what size tank do you have??? from all the fish you have listed as being in the same tank it would have to be huge....if its a small tank the ammonia could have gotten to a very high level..

my tank is 55gallons so i know that i was overstocked, but i was also way over filtered too, as far as getting anything into my tank that i have no clue, and i thought about saving some of the water to test it but i figured that with so many dead fish in the tank that the water would be so fowled from them that it would have been way to hard to try and track down what might have happened. and as for the frogs, from all of the reading and research that i have done i have found out that the africian clawed frogs are a completely aquatic frog and rarely, if ever comes out of the water.

since you had the tank for over a year, i would say an ammonia spike would be outta the question. i would say they got zapped too much with the cracked heater. perhaps those were the closest to it when it cracked.....wheres the csi team when you need them :-) i never had a problem with such a mass extiction except when i foolishly bought a red devil and put him in with the rest of my fish (WAYYYYYY to agerssive) killed half my tank in 2 days.

I hear your pain as I once had about 400 baby crayifsh and added too much brine shrimp and in a matter of 3-4 hours they were all dead. But Most likely the heater did the killing. I hope you can get your tank started but did you clean the gravel out as becasue there can still be mercury in the substrate.

hi
omg what a shame for the loss, my heater smashed completey and the elements where showing for some time 100 watt. i must have been lucky because non of my fish got the current oe shock from it, eventually i saw it and changed it