What is this?

[Richard40]

I can only think this is a flatworm in the substrate? Just noticed it tonight as well as some white (they look like fleas)? Bit worried about this, but read a little and said can be ok for a tank. My tank only 2 and half weeks in since started. Added new plants last Friday, some from AG and some from Plant of Mosses.

 

[Simon Cole]

Hi again Richard. The worms are likely detritus worms because they are clearly segmented and gut loaded, the fleas are likely seed shrimp ostracods. Both are meso-fauna. They seem to appear with Tropica soil quite reliably within the first few weeks. They help to produce mucus and this encourages bacterial growth and a health of the microbial community. They are also a sign of threshold water quality.

 

[Ghettofarmulous]

https://www.ukaps.org/forum/threads/id-a-bug-please.60775/#post-597879