Why do my fish have white spots?

It's a parasite called "Ich," short for Ichthyophthirius multifiliis, that appears on the body and fins as tiny white dots resembling grains of salt.  Consider this the common cold of aquaria.  Just about anyone who keeps fish will tangle with this problem at one point or another.  You can learn all about ich and how to treat it by checking out this article. 

I personally prefer to treat with aquarium salt and increased temperature alone.  The chemicals would damage my plants. 

For marine aquariums, ich is treated in a different manner, called hyposalinity.  So I just learned.

Ich is an obstinate problem in the fish-selling business, considering the stress fish experience during shipping followed by being introduced to crowded tanks with high turnover rates.

In summary: Ich happens.  Not a lot we can do about that.      

Comments

[makz]

How effective is salt against ich? I've always used malachite green (half the normal dose) with good results, however I've found that salt is very efective against mild bacterian infections.

[dsmfishgal]

If Malachite Green works for you, then I'd say stick with it. Salt works in conjunction with temperature increases and frequent water changes, but many chemicals work as well. It's a just a personal preference due to the plants and invertebrates in my tank. ;)