Snails? Where from?

[Simon D]

My tank has been snail free for about six months. I have not added any plants or fish and have just been doing weekly water changes under the EI dosing regime.

Suddenly, I find a trumpet snail (or something that looks very similar), how could that have got in there?

 

[rawr]

Trumpet snails tend to live in the substrate and be nocturnal so it could have been there for months without you noticing.