H. curtipes sticking to glass

[T3RR1B1L15]

Hi guys. I bought 8 Hymenochirus curtipes and they have been doing fine so far. They interact constantly anf are quite energetic.
However, last night, I noticed something strange. One of them was sticking to the glass in the corner of the aquarium a few cm above the surface of the water.
This morning, it has moved to the right. What worries me is that it looks like it's drying out.
Is something wrong with it? What should I do? Once again, sorry for any stupid beginner's mistakes I have made.

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[T3RR1B1L15]

Hello? Does anyone know anything about why it might be doing this?

[DonLisk]

Is it possible he is being harassed by the other tank mates? This would be my only thought since they would prefer being in the water than out.

[corientalis]

I also had one doing this. It turned out to be sick and died in a day or two anyway. I had some fungus infection in the tank that time.