Your pic isn't very clear but the foot looks like its infected and red dots can be a sign of poor water quality or septicemia. Is your tank cycled ? What are the water peramiters ? If you haven't a test kit do a big water change to be on the safe side, you can add almond leaves to prevent fungal infection of the feet, foot rot can be caused by a bacterial build up on surfaces ( not sand) so wipe down and decorations. If you could post some better pics, septicemia needs vet treatment, also post a head / throat PIC if poss, a swollen throat can indicate this.