Well I've put this of for a bit now so it's time for an update I never thought I would never have to do.
On the 9th (which is also my bday) I woke up about an hour earlier than usual, then went to check on the fish. As I walked in there were loads of fish floating at the top and lying on the substrate of the 40 gal. Somehow the heater malfunctioned on temps were over 100 F.
I moved the whiteclouds from the quarantine tub into the spec, and then all the fish from the 40g into the quarantine tub. Not sure what I would've done if I didn't have other tanks.
28/40 fish didn't make it.
5/12 cherry barbs made it
6/9 corys made it
The bn pleco also survived (thank god)
All harlequins, whiteclouds and the guppy didn't make it. 😢
Since I've only had the heater for half a year I went to the lfs and got a new one as the heater had a warranty.
I have no idea what I'll do now but I'll prob add all the fish back in soon once the I've dialed in the new heater.