Platy looks odd, need help!

[Lillyan]

Well, I have an adult yellow mickey mouse platy. She used to be fat and
jolly. Now she is thin and concave on one side. She lost an anal fin on that side, looks like there is some fungus there too. She is sharply in the shape of the old diamond image we all drew as kids. Active during feeding and about 10 months old I would say. Water and all is fine, nothing new. What could be wrong?

 

[FastFly67]

pictures would help
also exact parameters

 

[Lillyan]

Darker yellow is the sunken area, other side i thin but not sunk.
bottom of the fish is flat, no more curve like all my other Platy have, she had one too, but no more. Top is pointed, I think a bit of fin is missing too. Top fin is down, tail is fully out. She is active and zooming up and down the tank like usual. Seems to be a(one) scale sticking up in front of her top fin. No other scales messed up and color is bright and normal. The gray is where the 'fungus' is, doesn't stick out that much though.
AM-0, NI-0, NA-0

 

[mel_20_20]

Is this a heavily planted tank? Just wanted to know for sure, because if your tank is fully cycled you would be reading nitrate unless you have a lot of plants that are sucking up all the nitrate.

It does sound like there's some kind of infection, whether bacterial or true fungal, anything that looks like fuzz or cottony tufts would be one or the other... or sometimes both... but an actual photo would help if possible.

There may be other things going on, as well. Weight loss like that can indicate an internal parasitic issue, which can be a factor in developing other illness such as infection.

True fungus is often at the site of an injury, though a fugus could develop at the site of an ulcer or other lesion that is bacterial in origin.

As soon as possible, please provide the answers to those questions, we want to help and diagnosing and implementing measures to help her as quickly as possilbe will improve her odds at recovery.

Fungus has a long, whispy, hairy appearance; like a piece of food that has been overlooked in the tank for several days, whereas bacterial infection that is fuzzy looks more like wet cotton, or a filminess, or cottony tufts.

It would be very helpful if you could give us more information, really the answers to all the questions here:

http://www.aquariacentral.com/forums/showthread.php?t=180877

This may seem tedious... and it is pretty much... but the answers will help us think through this and assist you in figuring out what is going on and what we might want to suggest to help your Platy.

 

[Lillyan]

The tank is jam packed with plants. The girl had her left anal fin chewed off weeks ago, never grew back and she had some white on there, but then vanished. She got thin in the last 2-3 days.
55gal or so, over 6months, 2 filters both at or over 70gal rated.
windows on either side of tank same wall tank is against but no light directly going in.
w/c every 2 days or so because of white cloudiness that wont go away. 15gal changed, dont clean sand because i have far too many plants, i/e i cant reach the bottom lol.
all fish fed once a day at 7:30pm. tropical flakes usually, once a week frozen blood worms, algae wafers every 3 days.
tank had ich all over, most fish are clear, a few still have it. girl does not have/had ich though.

Idk what it is, but pics always turn out weird in that tank. other pics turn out clear and normal colors, but this tank has a weird haze and always blurry. I'll take her out in a cup for a pic if she is still acting normal. But she isn't a Betta, lol, they don't like out of water time.