White Spots on Tail Not Responding to Salt/Maracyn 2? (Not Ich. Thought it was Epistylis)

[B1gJ4k3]

My big Central America cichlid has developed some white spots on his tail fin. They're too big to be ich and only on his tail instead of all over his body (at least I think so. He's all white, so it's kind of hard to tell). They seem slightly raised, so I thought maybe it could be epistylis. However, treating with 3 tbsp/gallon of salt and food medicated with Maracyn 2--each for two weeks---has had no effect. I thought it could possibly be some kind of non-ich fungus and was contemplating trying Ich-X to see if that would help, but if it is a fungal infection, I would have thought the salt would have taken care of it?

I'm not sure what to make of it at this point. I don't think he could have injured himself on anything. All I have in his tank are big round river rocks and some bamboo (which for whatever reason, he seems to hate and is constantly attacking...🙄). He also doesn't seem to be eating as much and doesn't come to to the top of the tank when I come to feed in the morning. Although that could be a result of putting an auto-feeder on his tank over Christmas when I was gone for a week or just him pouting because his food doesn't have Garlic Guard on it anymore. He's the only fish in his tank, apart from a few snails, so it's unlikely (although not impossible) that something could have been introduced. Anybody have any ideas?

Parameters:
pH: 7.6
Nitrates: <20ppm
Nitrite: 0ppm
Ammonia: 0ppm
Temperature: 76-78
Hardness: Soft-ish
Buffer: Low

[Colu]

It does look like possible damage to the fin ray I would just monitor for now and update if anything changes @B1gJ4k3

[B1gJ4k3]

Thanks for weighing in, @Colu. I'll continue to monitor. It's been a few weeks now and it doesn't seem to have gotten any worse or had any other ill effects, so that's pretty much the conclusion that I came to. I'll probably take the bamboo out just in case (and because I'm sick of him attacking/rearranging them all the time)