I don't know what these things are, but I'm guessing they came with the Java moss I got a month or so back.

They're about 3mm long, mostly transparent and zoom around clearing paths through the algae.

Any ideas? They're not... poisonous are they?

Looks like planaria or flat worms. Usually caused by excessive feeding and too much waste in the tank. Harmless.

Initially I thought ostracods (seed shrimp) but then I noticed the subject said 'snail'

Do they look like tiny limpets with an almost transparent shell? Never more than 3mm (at a stretch)?

Probably Ferrissia (I think the species name is rivularis but not sure)

Completely harmless, usually come in on aquarium plants. Generally never noticed, they common in aquaria. Exotic.

Thanks for the advice, they're crunchy, so I'm leaning towards some sort of snail thing!

You ate one? :lol: :roll:

Not planaria then

Planaria are cute apparently you can get ENORMOUS ones overseas!

...I have odd tastes... :oops:

Wow, I love these little guys. They're pretty much unnoticeable in my tank, yet have cleaned ALL the thick brown algae off the back of my tank!

BEFORE:

20 DAYS LATER:

Here's what my tank looks like now, pretty crappy picture, but meh...