My clown loach scratching their mouth against sand

[Bis]

Hi just noticed one of my clown loach scratching their mouth against sand. Can't see anything in their face - white or red mark etc. Is this a parasite?

It's a new 4 ft tank just cycled, Ammonia 0, Nitrite 0, Nitrate 20 ppm, PH 7.8 , Temperature 85 F. Just have only 6 clown loaches.

[Greek]

Hmm, could You specify what exactly worries You in this behaviour? Clowns generally loves digging in sand

[Bis]

Greek, thanks for your reply and sorry for not replying sooner. As the symptom again back with the kids, I am back to see the replies. Are you saying that normally clown loaches may rub their mouth against the sand. This is exactly what they are doing here. Specially at the time of feeding I can notice this behaviour. Am I be able to explain the problem. I have never see this in any clown loach video or in real so am worried a bit.

[Greek]

Hmm, I'm really curious about that behaviour. Generally sometimes fish rub sand or decorations in a tank, but with whole their body - and that's normal if it happens from time to time. If it happens frequently it can sign a problem with ich. But it's hard for me to imagine how they can do it only with mouth I thought that we are talking about just digging in sand - like that.
Of course loaches presents a big range of techniques of digging - maybe You are just worried about sth like that.
One thing is sure - if it happens rarely, You don't have to be worried about it and just enjoy Your clowns' behaviour