Black Growth on Widow Tetra

[BK108]

Hello. I've only just joined today, mainly with the intent of making this post.

I have a Black Widow Tetra, which I noticed today after a water change has a black growth on its face. I've had little luck with seeking advice on my local community groups. I've had one opinion via tumblr, which was very helpful.

I'm unable to currently upload the video from my phone but it is available here: Revie-Steady-Go!

My tank is 4 ft long, around 200 litres and has had no live plants in over a year.
Fish include:
5 Black Widows,
1 Danio (hoping to get more when possible, this one survived out of a group bought from bad LFS)
1 Bristlenose plec
3 Yoyo loaches.

I haven't consulted my local fish store as when I last had concerns with a fish over a year ago they gave me melafix and an incorrect dosage amount.

I am planning to get the water tested as soon as I can.

 

[Delapool]

Hello,

Could lympho fit?

Tropical Fish Disease Identification with pictures and cures.

 

[BK108]

Hello,

Could lympho fit?

Tropical Fish Disease Identification with pictures and cures.

Possible. I'm now not sure if it could be parasites as today I noticed a white growth on the lump, whilst I was taking photos the white spot fell off. It's head's still black with a small bump but otherwise the fish is eating and has become more active again.

I've attached before and after images to this post.