Danio: Red Gills, Red Anus, Pineconing

[MichaelCrook]

Just had to put down a danio as out of nowhere (we keep a close eye... well we thought we did) our 1.5 year old danio had red gills and anus (as shown below) it also has pineconing/droopsy 

Just check the levels, 0 amonia and 0 nitrite. From our understanding pineconing is caused via internal infections caused by either bacteria or internal parasytes. So we are going to a vet to get a strong antibiotic treatment for the tank. But what else could we do to help (50% water change tomrow) like what other treatments?

Cheers.