Fish dying in quarantine tank due to temp swing?

Likely a dumb newbie mistake ahead: I think I know the answer to my question but figured I'd ask it here anyway....I bought 6 oto cats and 12 furcata rainbowfish and have them in a 5 gallon quarantine tank. I put a heater in there but it sent the water up to 82 degrees, so last night I unplugged it. This morning found 2 dead otos and another dead rainbowfish. Water was 74 degrees. Is the temp swing likely what killed them? I just got them 2 days ago but they looked healthy at the pet store and all the rainbows are eating well. A third oto just died mid day. Really mad at myself but am hoping this is my own doing rather than a problem with the crop of fish I bought.

 

Did you acclimate them to the water before putting them in? Drip acclimation is best if they haven't been in the bag for too long.

 

That sounds like a lot of fish at once for a 5 gallon, even if it was cycled (was it?). Could have been ammonia spike... I can be wrong, those are small fish and I don't really know how much ammonia they produce.

 

That sounds like a lot of fish at once for a 5 gallon, even if it was cycled (was it?). Could have been ammonia spike... I can be wrong, those are small fish and I don't really know how much ammonia they produce.

That's true.. I didn't notice it said 5 gallon. Could definitely be an ammonia spike

 

Otos don't do well in quarantine either. There's a good chance they haven't eaten in weeks between being imported, wholesale, pet store, and now quarantine.

 

Otos don't do well in quarantine either. There's a good chance they haven't eaten in weeks between being imported, wholesale, pet store, and now quarantine.

Is it best to add them directly in or no?

That sounds like a lot of fish at once for a 5 gallon, even if it was cycled (was it?). Could have been ammonia spike... I can be wrong, those are small fish and I don't really know how much ammonia they produce.

Good call...I just did a 50% water change but will test the water

 

Quarantining new fish protects your current fish.

Quarantining new fish is stressful to new fish. these fish have been tank surfing, been netted, been freaked out at the pet store on airplanes, seen Ph Shifts, and for wild-caught fish , they were ripped out of schools of hundreds of fish as well. If you do not have a good sized cycled, heated tank prepared, its even worse.

So you have to ask yourself, which risk do you want to take? And you can also ask yourself, do you trust the selllers? Did they notice anything troubling? Did they see issues and risk their good record of sales and sell you the fish anyway?

I have skipped quarantine more then I like to admit. And I have been lucky so far.

 

5 gals is too small for Otos, they need a big tank with lots of hiding spaces.

Also, catching wild Otos involves dosing the water with cyanide which stuns them and makes them easier to catch. By the time you buy them from your LFS they are already half-dead inside.

It's another reason why I don't buy Otos anymore