small snails have just appeared in my cycling tank

[crmpicco]

I am currently cycling my tropical tank preparing it for my new tropical fish. I done a check of my Nitrate level (which was out) last night and it was sitting well.

I looked in my tank this afternoon and noticed a small snail crawling up the glass on the inside. There was another slightly smaller one in another area of the tank. Where have these came from? Are they dangerous new fish i'll be introducing to the tank?

Are they apple snails or of any relation? I had the intention to put an apple snail in the tank, but I didn't think a snail would just appear ?

I have a batch of live plants in the tank and I have been feeding the filter a pinch of goldfish food every day to help cycle the tank.

Thanks,
Picco

[Lady Hobbs]

Pond snails. They have come in on your plants. They will also reproduce like crazy.