Platy covered in white stuff

I went to feed the fish today and found a platy covered in white stuff.

@Colin_T @Byron @Essjay

The photo isn't too clear - does it look as though someone has sprinkled salt over the fish?

I will jump in and suggest immediately raising the tank water temperature to 30C/86F, as I'm pretty sure this is ich. Spots look too large for velvet, though same heat works on both. Turn the heater up, but also do a major water change and raise the temp a few degree with this. Vacuum well into open areas of the substrate.

Yes it does look like that essjay. I will do a big water change. Also, the other fish appear to have the start of some white stuff on their tails and fins too

That's whitespot (ich). Byron has given you the treatment.

Essjay said:

The photo isn't too clear - does it look as though someone has sprinkled salt over the fish?

Click to expand...

That particular fish has now died

Do fish die from it?

They can do if it's a very bad infection, and it's in their gills.

How long do I keep the water temp at 30?

Lamie said:

How long do I keep the water temp at 30?

Click to expand...

Two weeks should be sufficient. The high temperature kills the ich in the free swimming stage (the only stage during the ich life cycle in which it is vulnerable, as is mentioned in the forum advice on this parasite), but sometimes one or two may manage to get through. But fish can deal with this, if not stressed. You do not want to see any spots after the two weeks. And it is stress that causes fish to succumb to ich.

Do regular water changes (meaning the regular once a week) and do a good vacuum into the substrate when you do. Replacement water obviously must be at the higher temperature. Make sure there is good surface disturbance, since warmer water holds less oxygen, and this reduced oxygen can stress fish.