Platy With Small Patch Of Fungus

[AshleyNZ]

I can only post a picture, tomorrow afternoon/night I will post more. Ive got him in 3L of water, with treatment and an airstone.
 
Small white spot of fungus under his top fin. Can see small stems attached to it when in water. His fins looked spiked, but are not shredded. He is very thin. He eats, but hovers around. heres a photo.
 
Indicated in red circle. Will update progress when I can.
 

 

[PrairieSunflower]

Is the tank that he was in previous to being transferred to the 3L container cycled?
 
3L is really too small for him to stay in while being treated, the water quality would drop far too quickly and counter the benefits of the medicine.  Is it possible to put him in a larger container?  There are many food storage or storage containers made from plastic that could be bought cheaper and used.  I'd aim for something closer to 10 gallons if possible so your water quality will not go down hill so quickly.  In a  3L container he'd need water changes 1-2 times a day which would effectively remove the medicine.  Pristine water is paramount when treating fungus.

 

[AshleyNZ]

I just put aquarium water in there, then the meds. He's Ok this morning.
It was 10.30 at night, what else could I do?
 
Um, 10G is like 30-37L isnt it? I have nothing that big.
 
I do have a 20L (5G) Tank, But no heater or anything for it.
Any ideas what i can do? Im away most of today.

 

[AshleyNZ]

Here's another picture.

 

[PrairieSunflower]

Anything bigger is better.  How are you heating the 3L container?  I am assuming you aren't unless you are floating it in your tank somehow.  You fishes chances are better in the 5 gal tank with the air stone than the 3L container as it would take longer for the ammonia the fish excretes to build up than it would in the small container.
 
Also, are you using a water testing kit to monitor the water quality for your platy?

 

[AshleyNZ]

I currently have him in my 30 or 40L tank, no heating, which is fine because its summer. The airstone is in operation, the pH is at 7. I do not know any other readings, as I do not have kits for that. 
 
The bucket was a temporary measure, as it was 10 pm, and its all I could really do right at that moment. 
 
No, im not using a testing kit. Can't afford one right now.