Invading critters!!! :(

[endlerguppy]

i have a 30 litre aquarium with 2 female guppies and 5 random livebearer fry.a few days ago i noticed a brown spec which was crawling round the aquarium glass(the bit where there is no water)and today i have noticed atleast 10.these critters are under 2mm big but when i put one in some water they started jumping.i did a 1/5 water change and added alot of aquarium salt.what are these bugs and how do i get rid of them?

[Obsidian]

Don't add "a lot" of aquarium salt, especially not all at once. You will want to make sure you are not changing the water to salt water. If you are going to add then make sure you add according to directions on the box, and go fairly slow with that.

Unfortunately I do not know what the critter is.

[Obsidian]

A good place to start your inquiry: http://www.planetinverts.com/what_is..._aquarium.html

[endlerguppy]

i think they could be springtails and also some of the fry have ich(i think) should i treat the tank?

[TheOldSalt]

I was thinking Springtails before I scrolled down to see you already figured it out, since springtails fit the description perfectly. They are completely harmless.

Ich on your fry, though, is not harmless. It's hard to treat fry, though. If there is ich in the tank, then yes, you'll need to do something about tit.

[weedkiller]

some chems will kill some fish for ich, was reading about a chem free way of curing and involves trning the heat up to about 85 (gradually i might add)
no expert there and im sure others here are or google the info rather than wait for answers