Hi I bought a clownfish 2 to 3 days ago and noticed a very weird line across its fins. It was a faint line on day two but now it’s a weird line across both sides. I know for sure it’s not ich, velvet, brooklynella, uronema. I’ve never seen something like this on a fish. Could it be something genetic. He was eating yesterday small brine shrimp but today’s he seems lethargic. Hanging around the top of the tank. I tried to feed him some pellets doesn’t seem interested. could it also be an internal parasite?