Zebra Danio fungus or columnaris?

[StormRel]

Water Parameters:

• pH ?
• Nitrates .5ppm
• Hardness Hard
• Nitrite 0
• Ammonia 0
• KH/Buffer ?
• Water Temperature 78F
• 10 Gallon tank
• Betta and 4 Zebra Danios

These parameters are my tank, however the fish in question I just bought from the store and am unsure of what parameters they were in before.

I just bought 4 Zebra Danios and one of them I noticed was a bit more ragged looking and swimming mostly at the top of the water.  Upon closer inspection he seemed to have a small white lump on his side and a few lesions(?).

I was super worried if it was contagious and immediately moved him to a separate 2.6 gallon tank, but he doesn’t seem to be moving much anymore and hasn’t eaten anything.

I’m a bit new, but I have dealt with Ich and I don’t think that’s what it is.  None of the other Danios have the same symptoms and seem fine.  
 

Any idea what it is?  Should I be worried the others are now infected including my Betta?

 

I’m so worried it’s columnaris 

[Colu]

with the  lesions  it could be a bacterial infection or a parasite infection what I would do is a course of paracleanse and maracyn together to cover all bases if start to see some improvement I would do another course of maracyn straight away and retreat with paracleanse in two weeks if he makes significant improvement after  the second course of maracyn I don't think you will have to retreat with paracleanse