My heater broke in my freshwater fish tank and I
could not replace it for a few days. The tank got very
cold and now all my fish have white spots on them.
What is wrong with my fish? Can they be treated?

Your fish have broken out with a very common parasite
called Ick. Ick looks like white salt crystals that can appear on any part of a fish. It is always around, like the common cold virus is for us, but the fish usually don’t pick it up unless they have been stressed in some way, and one of the biggest ways is going through a large temperature change. Being moved from one tank to another  and not changing water enough in the tank can also stress the fish out and lead to an ick infestation.
Ick can definitely be treated and there are great
medications on the market specifically made to deal
with Ick. Follow the directions carefully, as with
most fish medications the carbon in your filter will
most likely need to be removed and water changes are sometimes necessary during or after treatment.
Increasing the temperature of the water, while on
medication, can also help kill Ick off faster. If the
tank is normally kept at 76 to 78 degrees, then
increasing the temperature to 80 or even 82 degrees
can sometimes be helpful. We will be glad to recommend the right treatment for your tank.