Small white lice on glass and in water

[kwan]

I have a FOWLR tank which have cycled about 3 weeks. I then bought my first fish yesterday and everything seems ok until today. Today I find lots of tiny .5mm like lices on the glass and in the water. They have tiny little legs and a tail which to me is like some kind of pest. I have not notice any effect on the new fish.

But as a precaution I spoke to the LFS and I was told the pest is from the LR and I should not worry about it. I was told there are cleaner fishes which can clear them without using medication. I guess I am not sure whether I really trust what my LFS tells me and is hoping someone in the forum can tell me:

i) What are these white lices?
ii) Where they are from?
iii) Are they harmful to my fish?
iv) How can I get rid of them?

The problem is that I have cycled my tank with LR without light for about 3 weeks and I have not seen them at all until now.

[reefrunner69]

i) What are these white lices?

The lice (no s, singular is louse), are probably copopods or amphipods, they are beneficial detrivores in your system.

ii) Where they are from?

LFS was right, the LR.

iii) Are they harmful to my fish?

Unless they are predatory isopods, no they are not, they will actually be food for some fish.

iv) How can I get rid of them?

You don't, or shouldn't if they are pods

[kwan]

Thanks Kevin, that has cleared up my worries!

Kwan