Heater problem and then a whole host of issues

[malfist]

So about a week ago, I had a friend help me move my 55 gallon fish tank, and when we got it all set back up, we some how managed to not plug in the heater.

A couple days after that, I noticed my clown loaches looking unhealthy, and I tested the water and everything was fine. Nitrates were a bit up, but I was scheduled to do a water change in about two days so I left it alone.

That morning I woke up to 6 of my 14 fish dead, noticed the thermometer read 66 degrees and panicked. I plugged the heater back in, and turned up the house's heat too. (I normally leave it at 62 when I'm not home or I'm asleep) I removed the dead fish and went to work. When I came home from work, I discovered two more dead fish.

Since then the temperature has been restored and a second heater added to the tank, and several water changes have happened. However, I've still lost three more fish over the past couple days. Today was the latest loss.

I tested the water this morning and found the pH had spiked, from normally hovering around 7.4-7.6 to 8.2. I want the rest of my fish to return to health and fix the issues that seem to have been stirred up. Any ideas what would cause the pH to spike and how might I prevent more fish loss?

 

[Delapool]

Hi there, yikes - a bad run. I'll just go through some ideas (just ignore the wrong ones) and see if anything helps.

PH - have you tested the tap water or did you add any rocks?
Ammonia - did you check for that after the clown loach died.
Clown loach - I'm wondering if anything poisonous could of been added to the tank. Without knowing the other fish, I'd expect the loach to be more sensitive possibly to anything. (I did suspect the gravel bed but just read that it takes 6 to 12 inches of gravel to get an anaerobic layer where I thought there could be a problem if disturbed.) Any cleaning products possible?

The temperature I thought low but survivable and it seems to have happened a few days after. Any symptoms? Did the temperature go and down slowly?

 

[malfist]

I've tested the tap water, but it always comes out at 7. I'm assuming it rises slightly in the tank as the buffers in the tap water are used up.

Ammonia has stayed at 0ppm the whole time. I do a water change after spotting a dead fish to try and prevent spikes.

Nothing had been added to the tank, nor removed in over a month. The tank was established, and is well planted.

I was worred about the anaerobic layer in the gravel being disturbed during the move, but that was several days before the initial mass die off. The tank didn't get moved violently (it's a 55g after all) so it shouldn't have been disturbed. I don't vacuum the gravel during changes for this reason. It's about 3 inches of gravel.

My guess is that the temperature was that way for several days stressed the fish out. Especially since there would have been fluctuations (they're near a giant window, so heated during the day, especially cold at night) would have stressed them more. And the mass die off was after the coldest night of the year so far.

No chemicals other than prime is added to the tank, and only then during water changes.

The stocking was:
1x Common pleco
1x Black Ghost Knifefish (survivor)
1x Three Strip Glass Catfish (survivor)
1x pictus cat
1x Rope Fish
3x Clown Loaches
6x Bala Sharks

 

[Delapool]

I've tested the tap water, but it always comes out at 7. I'm assuming it rises slightly in the tank as the buffers in the tap water are used up.

Ammonia has stayed at 0ppm the whole time. I do a water change after spotting a dead fish to try and prevent spikes.

Nothing had been added to the tank, nor removed in over a month. The tank was established, and is well planted.

I was worred about the anaerobic layer in the gravel being disturbed during the move, but that was several days before the initial mass die off. The tank didn't get moved violently (it's a 55g after all) so it shouldn't have been disturbed. I don't vacuum the gravel during changes for this reason. It's about 3 inches of gravel.

My guess is that the temperature was that way for several days stressed the fish out. Especially since there would have been fluctuations (they're near a giant window, so heated during the day, especially cold at night) would have stressed them more. And the mass die off was after the coldest night of the year so far.

No chemicals other than prime is added to the tank, and only then during water changes.

The stocking was:
1x Common pleco
1x Black Ghost Knifefish (survivor)
1x Three Strip Glass Catfish (survivor)
1x pictus cat
1x Rope Fish
3x Clown Loaches
6x Bala Sharks

Yes, sounds like you're right on stress/temperature. My app has clown loaches at 77 to 86F so I guess pretty chilly for them. Hope it settles down now.