heater malfunction

[ABwildrose]

Well, I came home this afternoon and saw my 2 large male acei dead on the bottom. ( I wish RDfishguy still had his and I would snap them up in a heartbeat to replace them). My big melanochromis cyanerhabdos (?sp) was also missing and I eventually found him dead as well. He was such a beautiful fish. I even had compliments on "that pretty blue fish" from people walking by that could see him from the sidewalk

When I went to fish them out, I noticed the water was very hot. It was about 36 C. My heater was set at 22C and it was still heating. The power went off 3 times yesterday and once earlier in the afternoon. I wonder if that fried my heater or something. When I got the temp down to about 30C the other fish seemed to perk up and the ones that were practically laying on the bottom started acting normal again. The synodontis I have didn't really seem unusually stressed throughout the ordeal. I only have 1 dwarf bristlenose unaccounted for but I think he is probably OK. I always have trouble located all those guys during head counts.

Out of curiousity, how long can cichlids usually stand the high temps and how hot can the tank get without causing problems? I am kind of wondering how long the tank was that hot. I am sure they seemed normal yesterday.

[RD.]

Sorry to hear about the loss of your fish. Typically the survival rate of the fish at high temps would depend on the amount of 02 exchange in your tank. With a low 02 count (little to no surface agitation) and high enough temps one could lose everything in the tank within a few hrs. I've seen/read where entire tanks at 95-100F were wiped out in under 8 hrs.

It also depends on the species, and the size of the fish. Generally speaking the larger the fish, the more that 02 is required for normal metabolic function, and the quicker that oxygen deprivation will take place.

[ABwildrose]

Thanks for the info. I thought it strange that my 2 biggest fish died, but that kind of explains it. I don't have anything extra bubbling to break the surface tension for aeration. I do have a sump system, the water drains from the top and the water sprays through a spray bar across the media and then back into the tank through a spray bar set just under the surface. The water at the bottom of the tank really doesn't circulate well, I used to have an airstone down there to help circulate to water from the bottom, but the bubbles made the sump gurgle more so I stopped doing that. Maybe I will fish out an old pump and try moving the water around with that.