The 5g filter was the tank that killed my betta. Note: He didn’t die due to a disease, he died because the heater malfunctioned and roasted him.Either water conditioner is fine as they aren't the problem. The problem looks like disease. It is probably from the new fish as they weren't quarantined but it's a slight possibility that the old filter held parasites. Did you lose fish in the tank that had the filter in? I would follow Charlie's advise and medicate to save the remaining fish and clear the tank of the problem. Cory 3 looks healthy right now and the raspboras seem good.
I did clean it super well under hot water and took it apart and everything.
Yes, the HR’s and the NT’s seem to be doing fine, but the corys seem sort of stunned and they are that active.
What medication do you recommend I use??
I can’t do a water change right now, parents won’t let me because I have a Cyber Patriots thing.