What's the water temp in the tank?
Columnaris thrives at higher temps. Increasing water changes will help reduce the amount of it in the water, as will decreasing the water temp. It can also be treated using a gram negative antibiotic.
Body slime disease is usually caused by parasites. It can be treated by raising the water temp (and adding salt) and doing frequent water changes, or with antiparasite meds.
ETA: I can't see much in the photos right now. I'll look later when I'm on my regular computer.
Do you have any live plants in the tank?
Here's a good article about slime disease: http://www.fishchannel.com/fish-heal...e-disease.aspx