Help please! Huge mutant infestation in tank, please help, axi-s gills and tank walls are covered in it.

This weird thing first appeared in my tank a few months ago. I searched for any answers on what could it be, but didn't find anything specific, a lot of ppl said that It'll go away by itself. But this past week it's been taking over the tank and today I discovered that even my axis gills are full of it.
At first it was like tiny white upside-down umbrellas attached to the tanks walls and everything stationary inside it, but now its like white strings, up to 5-10cm in length. It is amazing how fast it grows, also. I emptied my tank a few days ago of all the hides and plants (they were covered also) and scrubbed the walls clean and its back now.
I'm thinking of emptying the tank completely and maybe giving it a little treatment with napalm or sth, because nothing seems to work for this thing. Any help is much appreciated.
Also...where would be the best thing to keep my axi while cleaning the tank?

DELFI Pilt > Pilt > P1090553 - the last 3 pictures are made today. One of axi, 2 of tank's wall that is covered in that thing.

Looks like some kind of fungus or hair algae. First positive step is to probably stop proving light.

Have you tested the parameters of the water? (PH, nitrate level etc)
Are you keeping fish with you Axolotl?
Is there anything in the tank that is decaying?

2 years ago a friend of mine had such funny stuff in her tank. It was a slime mold called Didymium nigripes. It suddenly appeared and some days later it was suddenly gone.

I couldn´t find a site in english about this species.

-Tina-

I couldn't really see much in the photo's , but your description of upside down umbrellas could be hydra.

I'll set the light timer from 13-22 to 14-21 then. I test the parametres every day, and they are okey now ( Nitrite, nitrate ~0, PH okay, GH is around 16 though) I had 5 neon-s and 3 other tiny orange ones but he has eaten all but 2 of the orange fish. And nothing in the tank anymore except a moss-ball and 2 stones. ( I took everything out to clean the tank but then found out that its also covering the sand)
I'm not sure but he seems to have 2 white spots under the belly, can't really get a good look atm, but will look tomorrow morning. It also looked like there was a bit of skin loose.
Any suggestions how to fix the tank? And can I keep him in a seperate cointer for a week? To re-start the tank.

I don't know what it is.

Yes, you can keep the axie in a separate container for a week. Be sure there is no uneaten food allowed to be there, and do a partial or total water change daily.

Does your tank have any live plants, or anything else alive besides the axie?

My tank at the moment has 2 tiny fish and a moss-ball. It had another plant but it got taken over by the mutant lifeform and I'm keeping it separately until it's free of it.
I guess I will put the axi in some box tomorrow, take out everything and clean the tank as thoroughly as I can.
Few questions about keeping him in a box for a week: if it were about 2-3l container? I'll do partial waterchanges every day, but what about oxygen in the water as it's not moving and doesn't have a pump? Also my tank temp is ~15, room temp is 19-20, I guess he'll be okay with that for a week?

Axolotls will do fine without a filter or an air pump. Just make sure it can easily gulp air at the surface. Those temperatures will also be fine.

Also keep in mind that if you take everything out of the tank and clean it, you'll also have to re-cycle your tank, as you'll kill off all your beneficial bacteria in addition to the stuff you're trying to remove.

I cleaned my tank and set it up about 4 days ago. On the first day I filled it with water, bunch of stones and a wooden hide, put in an air pump and a pinch of fish-food, and it has been settling since then. I cant put in the tiny filter as I'm afraid it'll spread the hydra or what ever it was, back into the tank.
Water readings after doing a 25% water change are:
CL2 - 0
PH 6.8-7.2
KH 3-6
GH 16
NO2 0
NO3 10-25
I don't have ammonia tester =(
I'm wondering when can I put him back in, as he doesn't look that happy in that tiny bowl.

I haven't put in the plants yet either, as I'm afraid the might have bits of hydra still on them. I will put them in tomorrow after I give them a good washing (with water only of course)

It's not hydra. I'd stay with the slime idea. It seems like you need to keep the tank clean.We talk alot about "parameters" and ignore lots of other water quality issues in the process. If you've had this animal for a while and only recently had to deal with this issue I'd say the water change is warranted. If the problem returns after that, you need to look further for a cause. Plants might not be a bad addition to help keep the water sweet.

Things to consider would include what you feed and how you feed, how often do you do partial water changes, what water conditioner do you use, what are your tank fixtures made of, what else do you put in the tank.