Sick Glofish please help!

[LuisRuiz89]

I've been raising glofish for a few years and this happened... One of my yellow tetra glofish (Limon) started having a weird growth on his head, around the brain I cleaned the tank throughoutly and left on a vacation with my family, leaving my parents in charge of my fish. They said everything was alright, but they only came inside the house to feed the fish once a day. We live in a place with frequent power outages, so maybe a lack of oxygen could have done something with it? When I came back, I pampered them so much, but the black abnormality got worse and his eyes are now popping/red fins.

I checked the water parameters and everything's fine, none of his bros seem to have the same problem so I'm sure its not a fungus. I would do anything to save him, so any advice is fine! The photo is the best I could take, he hides all the time...

Please help

 

[Aiken Drum]

Try and fill out what information can answering the following questions.

What are your tank parameters (ammonia, nitrites, nitrates, temp, pH)? Please give exact values.

How large is the tank? How long has the tank been set up?

What type of filtration are you using? Please give the name and number (i.e. Fluval 304) and amount of*gph*if known.

How many fish are in the tank? What kinds of fish are they and what are their current sizes?

When is the last time you did a water change and vacuum the gravel? How often do you do this? How much water do you remove at a time?

How long have you had the fish? If the fish is new, how did you acclimate it/them?

Have you added anything new to the tank--decor, new dechlorinator, new substrate, etc.?

What kind of food have you been feeding your fish, have you changed their diet recently?

Can you quarantine the fish to ensure whatever is effecting it doesnt effect the other fish?