What is this

[K_Red_Raider]

This morning I noticed a red/rust color on my yellow tang. It is on it's fin and was wondering if anyone had any idea as to what it is. It is acting like normal, eating and swimming around the tank. This is the best pic I could get and I will work on getting some water perameters.

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Thanks
Kevin

 

[K_Red_Raider]

I was thinking it was probably an infection from an injury esp after looking at the powerpoint and my flame angel has been chasing everything around my tank lately.

Here are my tank water numbers anyway
ph 8.24
temp 79.1
salinity 1.024
calcium 450
alk 9.5
ammonia 0
nitrate 10--i know that I feed too much but my fish and corals are fat and happy
phos 0
mg 1380

Thanks for the imput!