Blue/black arowana

[Kevinc]

Hi I have a 40cm blue arowana yesterday I noticed a dark red large spot on one of her fin but I dont know what is it
maybe someone with a lot of expirience know
i dont know if it is a parasite or tumor
thanks in advance
kevin.

 

[Fishman Dave]

Just a little further information please.
Is there any decor in the tank or slightly above which the arowana could have caught itself on ?
I assume you have had the fish a while?
Only became noticed very recently?
So not something you have seen getting steadily worse?
Please also confirm that mark is actually below the fin and not on it.
Is the mark raised ?
A lump?
Or just red and not raised?
Hard to see in this photo, thanks.

 

[Kevinc]

I bought the fish 4 weeks ago untill yesterday she had nothing
Regarding decor i have some roots on a side but she dont go next to them
It is actually on the fin cause its moving with the fin it looks like its not raised but going outside the fin
I know the pic is not that good but shes always moving so is not easy
Shes not scratching her self with objects really i dont know what is that
Thank you

 

[Kevinc]

Its hard to explain how it looks like cause shes always moving and i never seen something like that on a fish at first I thought it was a bite from severums but its not than my mind went its a parasite but shes not scratching so maybe something else

 

[Lijzeej]

You feed live feeders?

 

[Kevinc]

No till now never gave live feeder fish to her but now she looks ok i think it was a scratch cause later i so the red scale falling