Oscar With A Bump/blister On Forehead

[EGFishKeepers]

Just noticed a bump/blister on my Oscar's forehead.  It's maybe a quarter inch around.  It is in an over-stocked tank at the moment but all the other fish look fine....I'm trying to rehome some of them but its slow-going.....
 
TIA

 

[the_lock_man]

TIA of what?
 
If you are asking what the bump/blister might be, then you need to post a photo of it.

 

[fluttermoth]

How big is the tank, exactly what fish are in there and have you tested the water at all (and, if so, what were the numbers)?

 

[EGFishKeepers]

It's a 55 gallon tank....All the fish are juveniles....2 Oscars, a Jack Dempsey, a Green Terror, 2 Convicts and a large Plec....I'm well aware the tank is seriously over-stocked....I've re-homed a couple of fish including an Arowana....The tank is new to me and most of the fish came with it...Now I'm stuck and trying to re-locate most of them.....
 
The bump is gone from the Oscar's head...It left as fast as it came.....
 
I've tested regularly and just had my LFS test it....
 
Latest numbers
 
  Ammonia 0
  Nitrite 0
  Nitrate 10
 
I'm doing a 50% water change once a week.
 
TIA = Thanks in Advance  (I'm an old guy and this is a leftover from my newsgroup days)

 

[fluttermoth]

It's very difficult to rehome these sorts of fish, I feel for you

The bump/blister could have been a scrape (my oscar sometimes scrapes his forehead when he's moving his decor around) or a bite from one of the other fish.

Keep a close eye out, and watch the nitrate level; you may need to up your water changes as the fish get bigger.

 

[the_lock_man]

TIA = Thanks in Advance  (I'm an old guy and this is a leftover from my newsgroup days)

 
 
LOL, I know what TIA means - but you hadn't actually asked anything in your original post.
 
Best bet, like I said before, is to post a photo.

 

[EGFishKeepers]

Ahhhh....
 
He looks fine now.....