A "friend" abandoned a 90 gallon tank at my house and I ended up setting it up for my fish. Luckily I only moved half my fish into it cause the heater that was in it (a stealth pro that I just read was recalled) burned up while I was at work. The tank itself is physically fine, but there was essentially an oil slick on the surface and it smelled like burned plastic/ electrical. I skimmed the surface as much as I could and did a 50+% water change last night and everything seemed fine. Everything even seemed fine this morning when the lights came on. Nothing was dead. Within the span of 3 hours, all of the cardinal tetras are either dead or swimming erratically (swimming loops and corkscrews and a lot of upside down swimming). Then rummynose tetras started doing the same. The cardinals seem too far gone so I didn't move them to the other tank, but only one of the rummynoses I moved to the "non-toxic" tank is still alive. There are hatchetfish, a couple corys, ghost shrimp, assassin, pond and trumpet snails and a bunch of plants still in the "toxic" tank that seem to be doing ok. Should I just move everything back to the smaller tank and cycle the 90 gallon for a while? Should I just let it ride and see what happens? Is the 90 gallon just a toxic death trap now? Any advice would be greatly appreciated. I'm going crazy here.

I would move everything out of the tank and replace all of the water if you can. I don't know the components of the heater but if it is chemical then you should start over with the 90, break it down and reset it up like it's new IMO. If you let it ride out you could lose more fish.

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75gal - 3 tinfoil barbs, 2 convict cichlids, 1 syndontis, 1 fire eel, 1 pleco
55gal - 6 black neon tetras, 3 lyretail dalmation mollies, 3 emerald green corys, 2 albino corys, 1 zigzag loach, 1 kuhli loach, ,1 rubber lipped pleco, 1 otocinclus, 1 goldfish

Or..... it could be just the temp shift!.. What were you keeping it at typically and how low did the temps get? But if other fish are still surviving.. I'd not worry and attribute the fish loss as a radical temp shift... If the temp drop wasn't over say 8 degrees F, I'd follow the previous advice... Drain it, clean it.. start all over. Bill in Va.

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12 Tanks, 900 gallons. Discus/Angels/Malawi/Lake Victorias. Just added a 135 & 2 - 29's..

The tank was about 70 degrees F, and didn't drop below 65 after the burn out. I moved all the fish and all the ghost shrimp I could catch back to the 55 gallon. They seem ok. I left the whitecloud minnows in the 90 since they were free and I guess to see if the tank is doomed or not. Will big water changes and cycling the tank get rid of everything? This tank will be tough to completely break down and clean. There's a lot of plants and I'd like to save as many snails as possible. Assassins mainly.

have you done any testing of the water? is the tank still cycling or was it running already when you "adopted" it?

welcome to the site.

Did an ammonia test. That was fine. Don't have PH or hardness test here. My friend is bringing some by tomorrow. Not that I'm worried on that front. It's never been an issue. Copper test might be useful. The tank has been cycling for over a month after a major cleaning.

Ammonia, nitrites and nitrates are the most important test kits, I wouldn't worry about the others too much.

Ammonia, nitrites and nitrates are within safe ranges. The whiteclouds, snails, and a couple shrimp I missed are doing fine. A couple rummynose died in the upstairs tank but I'm chalking that up to wildly varying temperatures over a two day span. Did another big water change and I'm going to let it cycle for a month or so. Thinking of adding a few more plants just so there's more life to absorb any bad stuff left over. Thanks to everyone for the responses. I've been reading through this forum for a while now it's answered a lot of my questions. I never had a need to post before the heater dilemma.

I'd use as much bio material as possible including the gravel etc and set it up as new. If you can get bio material from another tank and add some safe start live bio stuff that would help. Never heard of a heater doing that. And oh...pick up a new heater.

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Hoopman
Sunny Orlando FL
55G W/Angel, loaches/cats, tetras, rasboras, Two Bio Wheel 350's (8 cartridges and 4 wheels) Dual T5 ATI bulbs which are blue & blue-plus (white), give a saltwater tank look/moons. - 37G w/Angel, Mystery snails, tetras/cherry barbs. Dual 24 inch T5 with same ATI bulbs/moons. Bio wheel filter (dual cartridges and one wheel) and Aqueon single filter Bio cage cartridge, both designed for larger tanks. n

move all living things, drank it, fill it back up and let the filter run for a day or two and see if the residue and smell are gone.

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin