Clamped fins are usually caused by poor water quality, chemicals in the water, protozoan or bacterial infections.
The fish is covered in excess mucous (creamy white film over the body and fins) and this is normally caused by poor water quality or something in the water irritating the fish.
How long has the tank been set up for?
Have you checked the ammonia, nitrite, nitrate and pH of the tank water?
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Wipe the inside of the glass down with a clean fish sponge.
Do a 75% water change and gravel clean the substrate every day for at least a week. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.
Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use them. Tip the bucket of dirty water on the garden/ lawn.
Increase surface turbulence/ aeration when using salt or medications because they reduce the dissolved oxygen in the water.