Albino Tiger Barb Red Swollen Snout

I have a 75 gallon cycled and planted tank that I set up in May of this year. I have a heater set at 78 degrees Fahrenheit. A HOB double filter with bio wheels (Marineland Penguin 350). Air pump with a port splitter running 2 airstones and a bubble wand. In the tank I have the following:

3 Albino Tiger Barbs (I had 4 but lost one Monday)
4 Tiger Barbs
4 Rosey Glass Barbs
1 Albino Rainbow Shark
2 Blue Dwarf Gourami

My water parameters are as follows:
pH 7.6
High Range pH 7.8
Ammonia 0
Nitrites 0
Nitrates 40
*Water is tested with API Freshwater Master Test Kit bought in May 2018.

About a week ago, I added 3 new bundles of plants I bought from a new pet store that I hadn't bought from before. The next day, one of my albino tiger barb's mouth looked red and swollen, it's snout distended and it was like he couldn't really close his mouth. I kept looking and didn't' see anything fuzzy or white, cottony looking, so I thought maybe I had accidentally dropped one of the bundles of plants on him as they came wrapped in that weighted grey tape on the bottom. I kept an eye on him for anything growing and nothing ever did. Until Sunday night when he had a couple of spots of ich. I finally made it to get ich meds (Herbtana) Monday afternoon but when I got home, he was gone. I debated treating the whole tank for ich until this morning when I decided it was probably best. I did a 30% water change, removed the carbon from the filter; replaced it with filter pad but left my bio media in. I added a dose of the Herbtana. All seemed fine.

I just checked my fish and now I have another Albino Tiger Barb whose mouth and snout look exactly the same as the first one that died, except this one can still open and close his mouth. I am at a loss. If anyone knows what this is and could advise me on how to proceed, I would greatly, greatly appreciate all help!!!! Thank you in advance!!! Adding 2 photos to try and show what it looks like but they aren't the clearest.

 

Are his mouth stuck open? Btw. Your nitrates are high try to lower them under 20.

99% disease that have mouth symptoms are caused by bacteria so you can quarantine him and use antibiotics

 

I just did a 30% water change so the nitrates should be lower. Waiting until later today to re-test.
Which antibiotics should be used? Are antibiotics readily available at pet stores or do they need to be ordered online? And can they be used in conjuction with ich treatment?
At this point, I feel like it would be better to treat the whole tank as this is the second tiger barb to come down with it. By now it has to be "in the water" I would think??

 

Are his mouth stuck open? Btw. Your nitrates are high try to lower them under 20.

99% disease that have mouth symptoms are caused by bacteria so you can quarantine him and use antibiotics

No, so far his mouth is not stuck open and he continues to eat. I did notice last night that he swam right beside another albino tiger barb (actually touching at the sides) and seemed to be nipping or sucking at the other one's mouth.

 

I don't know what antI bacterial meds you have in area but every lfs have some. I would increase temparature for 2 weeks for ich and for probably mouth rot/fungus I would use that meds but I'm quarantine tank if it's possible.

His immunity went down so he was attacked by bacteria then ich so.

If you remove him you can medicate main tank for ich but don't mix meda.

 

He didn't make it...... Pretty sure he had septicemia but didn't find that possibility until yesterday.