Help eradicating what i think is Columnaris

[Kennakm]

INFO/BACKGROUND REQUESTED BY ADMIN: (keep in mind i really am panicking and have no idea what i am doing to get rid of this, nor am i sure it's columnaris... please be nice and helpful i know I've made some mistakes)
TYPE OF FISH AFFECTED-> 4 assorted fancy guppies.
SYMPTOMS -> white patches (not like fungus), fin and tail rot, popeye in both eyes (in one guppy, who has no patches or rot). i think it's columnaris.
PARAMETERS -> Ammonia: 0ppm, Nitrite: 0ppm, Nitrate: 10ppm
TANK SIZE/ TIME ESTABLISHED -> 10g tank, it's been cycled for about 6 months. it was a rough start, fish in cycle. didn't know what i was doing. much has been learned.
TYPE OF FILTER -> the Aqueon HOB filter that comes with the 10g Aqueon starter kit. i can find the user manual if it's that important. no carbon filter, sponge used instead. pothos has been growing in the filter for about 4 months. rinsed it out to increase water flow a couple weeks ago with old tank water. ended up getting clogged, has to take it apart and get impeller going again. working great for two weeks since all that.
LIVESTOCK-> 6 cory catfish (3 pymgy and 3 "dwarf") and 10 guppies, 2 pregnant females and 8 juvenile fry (i think about 3 months old)
LAST WATER CHANGE/ SCHEDULE ->water change a week ago, about 50% because i had fallen a bit behind and nitrates were a little high for my liking. i do a water change whenever nitrates exceed 20ppm.
NEW ADDITIONS -> a pair of red cobra guppies were added about a week and a half ago. i got them from a very reputable local aquarium but they were new and not fully treated by them yet. the male had minor finrot which i figured was healing. the female looked fine. well i'll never make that mistake again.
DIET/ DIET CHANGES-> baby brine shrimp and daphnia alternated. fed every other day. (fed one dose of Everything Aquatic Anti-Parasite Quad Flake in a quick panic but then i realized this is bacterial and stopped that immediately)

so heres the story:i have guppies. as you know they multipy quickly. once my tiny 10g tank started getting full i stopped any attempt to save the fry and began cycling a 29g tank. in the meantime more fry were born, but only 2 or 3 would survive each time. i have two mature females that alternate giving birth every two weeks or so. no adult males. i also have 2 nebula steel fry that i purchased from a local aquarium. there were 16 other fry in this tank along with 6 cory cats before i could get my 29g cycled. then i switched over 8 of the juvenile fry to the 29g tank. so 8 currently in the 29g and 10 in the 10g, plus 6 tiny cories.
well, this was the setup i had when i found red cobra guppies at this aquarium i visit a lot. i had been wanting some cobra guppies badly, but noticed the males seemed to have deteriorated fins. but otherwise healthy looking. i had kanaplex at home, an antibiotic, and figured it would be fine to just add a pair of red cobras to the 10g and treat all the fish for bacterial infection just in case. (i don't currently have a hospital/quarantine tank set up, and didn't want to introduce any bacteria to the 29g). this was stupid in retrospect. within a couple days the female developed saddleback (white patch like a saddle on her back), and a day or two after the male died as well. despite a full 3 day treatment of SeanChem Kanaplex. I ordered Furan-2 immediately. i've started the Furan, the tank has been dosed 2 times now and today i will do a 25% water change as instructed. I added 2 tbs of aquarium salt to the tank (and then learned this isn't great for catfish ugh) a couple days ago as well. I've done two doses of Lifeguard.
3 days ago, one of my blonde tequila sunrise (i think) juvenile guppies developed a white patch around his dorsal fin. it's only gotten worse and now he is very clamped and barely swimming. yesterday when i checked on them, one of my 2 adult female guppies has popeye in both her eyes. it looks like she is wearing white magnifying goggles. today she is having a hard time staying upright.

I am at a lot for what to do here. i don't want to lose all the guppies in my 10g. but they are starting to drop like flies. i can't transfer any healthy ones to the 29g because i don't want to risk infecting those (they seem healthy and happy). i read later that furan-2 and kanaplex should be used together? should i do a big water change and start over? should i start cycling a new tank and turn this one into a hospital tank and keep medicating? switch them over to a clean tank and medicate and aerate and add prime/ do big water changes?

what's the best way to save these fish. I'm on a budget but could afford a new filter, i have a spare ten gallon. i have lots of medications. if anyone knows how i can get rid of this columnaris, and save most of my fish, PLEASE EXPLAIN HOW!

[charliebankston]

Well, your on the right path. Unfortunately, columnaris is hard to eradicate and can kill quickly. Antibiotics are the only thing that works on bacterial infections. Furan-2 added to the water helps alot, but it's a sulfa drug, not really an antibiotic. So it's OK to use with real Antibiotics. It'll slow down and kill the bacteria in the water column, but prob won't cure the fish. Make some medicated food with the Kanaplex and see if you can get them to eat it

[charliebankston]

Maybe this will help
https://aquariumscience.org/index.php/12-treatment/

[Kennakm]

i ended up learning to use a sulfa based medicine as directed and if fish keep getting ill to use antibiotic, then i'd need to cycle my tank again. i have a hospital tank going but I'm worried all the fish in the main tank are already infected/ exposed to the bacteria. so I'm going to treat the hospitalized visibly ill looking fish, and the healthy looking fish in their main tank.
I guess i will end up having to cycle my tank all over again. yikes. don't know where i'll put my fish in the mean time.... i guess it's time to master a fish in cycle?

[charliebankston]

Haha! Fish in cycle isn't too hard, that website has alot of good cycling info too

[Delapool]

Going to be tough it sounds. The furan 2 and kanaplax can be mixed together. Repeat dosing may be needed. The catfish should be ok with the salt. Ime keep temp same or slightly lower.

This is only an imo but with serious bacterial infections I put down fish that look unlikely to make it. See how it goes after dosing.

[charliebankston]

Originally Posted by Delapool

Going to be tough it sounds. The furan 2 and kanaplax can be mixed together. Repeat dosing may be needed. The catfish should be ok with the salt. Ime keep temp same or slightly lower.

This is only an imo but with serious bacterial infections I put down fish that look unlikely to make it. See how it goes after dosing.

Good advice! I 2nd this

[Delapool]

I had one really bad summer of it. Tried a couple of hospital tanks where I could try anything and everything (albeit lots of mail order as over the counter antibiotics heavily restricted here). Pretty distressing. Larger fish seemed to have a better chance - possibly as could notice it sooner. Success rate was dreadful though.

I’ve tried furan 2 about three times in the planted main tank and each time it’s pretty much either wiped out plants or growth hits a brick wall for several months so I’ve gotten very wary on that one in main tank as pretty expensive to replant. Weird one. Much to the bemusement of cichlid keeping friends.

Medicated feeds and other meds not so much an issue strangely.

Could try a good UV filter (slow flow rate). I’ve thought these can help. Still found that infections can occur but thought it did make a difference. I don’t bother with them now though but that was partly just to simplify a bit.

[charliebankston]

It seems like bacterial infections hit all at once. In different tanks. And different issues. Prob just my imagination