Odd black Cory behaviour
Hi, so this Cory has been having a hard time. It seemed to develop fin rot which hasn’t gotten any worse but its skin looks a bit paler compared to the other black corys. We also got hit with a canallanus outbreak. Through all this (round 2 of worming treatment was yesterday and did a water change today) he’s been quite lethargic on and off for a couple of weeks. However today it’s just aimlessly swimming around the tank non stop. I feel like it’s likely not a good sign. No signs of the red worms anymore and all other fish are behaving normally. Testing water with API test kit and ammonia is 0, nitrates have been higher than I like (20-40 at times) and there’s been a slight increase in algae growth so I’m working on small and often water changes for a while to get water quality back under control. Also adding tannins. Anything I can try for this guy? Unfortunately we don’t have a hospital tank available and feel like any extra stress might tip him over the edge but also don’t want to risk passing issues to the other fish. Thanks for reading and any advice!