possible columnaris?

[doktor zhivago]

Got 6 corys for a new 20 gallon tank I've been setting up about a week ago. The tank had a filter from my other tank put in so it was cycled and parameters were great before I added fish. I moved 12 harlequin rasboras from my platy tank to the new tank about two weeks ago. Tank was still cycled and parameters were good. Fast forward a couple days after finishing stocking and the corys have been sick with what looks like cloudy patches on their backs (pic attached)

The rasboras and the honey gourami also in the tank still seem symptom free so I think it was just the corys carrying the plague. Two corys died yesterday and caused a spike in ammonia and nitrites. I immediately began treating with maracyn 2 per the package instructions but I lost another cory last night (the fish picture above).

I'm going to finish the maracyn 2 treatment but is there anything else to watch out for?

Current parameters:

Ammonia: <0.25 and dropping after removing dead fish

Nitrite: same as ammonia

Nitrate: 20-40ppm

Temp: goes up to about 81 during the heat of the day but usually 78 or so

Both kinds of hardness are off the charts (my water is liquid limestone)

pH is 8-8.2

No chlorine or chloramines

 

[doktor zhivago]

retested with api just now:

ammonia back down to 0
nitrites 0.25 (i suspect from the maracyn messing with the bacteria)

[doktor zhivago]

On 6/26/2024 at 8:56 AM, Nora Loves Corys said:

0.25 ppm nitrites is very high.

it was 0 for several days after stocking the fish so i don't think the filter was the problem. the tank it came from has like 20 something platys and shrimps and snails and bristlenose pleco in it as well as the 12 rasboras originally. i think it climbed up because there were two dead fish rotting overnight yesterday and another last night. i added the antibiotics last night (before the third fish died) and the ammonia dropped back down in a few hours so i was encouraged but i'll keep monitoring the nitrites throughout the day.

 

On 6/26/2024 at 8:56 AM, Nora Loves Corys said:

Salt can be used to treat nitrite toxicity as described here, and it can also help with some parasites, fungal/oomycete, and bacterial infections.

i've added some salt but i don't want to get too crazy with the plants in there. just a few tablespoons of fritz marine salt i have for the bbs hatchery. i also gave a squirt of fritz complete overnight to take the edge off anything crazy that might happen chemistry wise.

speaking of bbs i fed some to the tank this morning and everyone else looks really healthy and strong. the remaining 3 corys don't have any fuzz patches on them and seem very energetic and ate well. some extra salt from the hatch water probably didn't hurt either.

[Colu]

Panda Cory's like cooler temperature 68-77°F it could be stress of the higher temperatures that caused them to become sick that looks like over production of the slime coat that can be caused by a bacterial infection poor water quality such as ammonia nitrite  I would add an extra air stone complete the full  course of maracyn2 if you have extra cycled media you can add from your other tank that will help lower your  ammonia and nitrite 

[doktor zhivago]

On 6/26/2024 at 6:44 PM, Colu said:

Panda Cory's like cooler temperature 68-77°F it could be stress of the higher temperatures that caused them to become sick that looks like over production of the slime coat that can be caused by a bacterial infection poor water quality such as ammonia nitrite  I would add an extra air stone complete the full  course of maracyn2 if you have extra cycled media you can add from your other tank that will help lower your  ammonia and nitrite 

i turned the heater down a bit and then turned the ac down in the house so it won't get above 78 anymore.  i tested this morning and my pH had jumped from 8 to 8.2 but then i remembered i added 4 tablespoons of marine salt (duh).... ammonia and nitrites are back down to 0 overnight. i added a second air stone last night as well. everyone seems good. i got away without a quarantine tank for a while but i think i've learned my lesson this time!