Skin And Behavior Issue

[spaceystation]

I noticed about 3 days ago my gourami Started to rock back and forth. But he always swam weird so I just ignored it. But today I came home from work and on one side in the middle of his body, he has a nickle size patch of missing scales. I know he will probably die ugh but I just want to know if anyone knows what this is for sure? Btw don't hate me but yes we have been horrible with cleaning lately. Its probably bacterial or parasites but I just wanted to get a better opinion. And if other fish can get this. Thanks.
I wish I could post a pic

 

[Ruskull]

My Gouramis have done that when the Nitrates are high. Never had an issue with missing scales in a patch though, maybe you should some aquarium salt? Depends on what other fish you have of course but the theory is that the fish can handle a bit of slat while some bacterial or fungal infections can't. Adding salt also increases the natural slime coat on the fish which might help in this situation.

Whatever you decide to do should start with a huge water change. What are your test results? What size tank? W hat other fish do you have in with it?