Pygmy Corries Are Dying- Is It The Heat?

[fishnovice]

I adopted 3 pygmy corries 3 weeks ago. They seemed fine at first, settling in nicely with my 12 other corries. then 5 days ago one died and now I've just found another dead one. Could it be the heat? Even though I unplugged all heaters 10 days ago, the water in all my tanks feels hotter then it normally does with heaters on.
The only other thing that's been different is that I moved my weatherloach to the corries tank a week ago and found the first dead cory 48 hours later. Is this a coincidence or is the weatherloach a killer? He seems very peaceful and has never attacked other fish before, though admittedly he's used to large tankmates like goldfish and gourami.It's definitely a weatherloach, not a CAE

 

[sampster5000]

Make sure to keep the air stones running. My cory's get incredibly stressed when I raise the temperature over 80. You never know about the fish being aggressive until you witness it. Some fish will stay passive while you are up close to the tank watching but will go back to bullying when you walk away. Others will only bully at night. Hard to know.

 

[fishnovice]

Make sure to keep the air stones running. My cory's get incredibly stressed when I raise the temperature over 80. You never know about the fish being aggressive until you witness it. Some fish will stay passive while you are up close to the tank watching but will go back to bullying when you walk away. Others will only bully at night. Hard to know.

Running 2 filters with bubbles at surface. Heater has been unplugged for 2 weeks.Hopefully heatwave is over now