Help Cory catfish has strange growth, need help Identifying

[Burtle]

The above picture was 2 days ago
The picture below is from today

One of my corys have a strange growth on the side of it. I am not sure if it is a cut/bite mark, or a fungus. I am looking for advise.
I have a 20 gallon long tank, I switched to sand last week as one of my 3 corys died. I checked closer and there barbels are gone. I recently got 9 new fish all at once, so that may have caused a change. I originally had 2 corys, and 2 gouramis, I now have 6 coys, 2 gouramis and 5 Danio pearls.

pH 7.6
Ammonia 0 ppm
NO2 0ppm

The effected cory appears to not be that reactive. When I moved something next to it it wouldn't swim away. Eventually it swam to the corner and two other corys where swimming and pushed it trying to get food nearby. It rolled on its side then slowly got back up. Currently it is spending most of its time resting on decoration near the top of the tank. Any advise will help, Thank you

Edit, I noticed that this white clump woud disappear, just recently it started to swim around frantically upside down before floating at the top. The white clump is gone and now a large red spot is there, blood? I moved it to a bucket with an aerator and it may be dead. I think it has a small worm hanging out from its side away from the wound but I can't tell, it may just be skin peeling. Do I need to treat my other fish now?

 

[MissNoodle]

I would start doing some heavy water changes and dose with Seachem Prime. I suspect you may have some bacterial infections with the cories, and possibly also an ammonia spike with adding new fish. The prime and water changes will handle the ammonia, and also keep the water much cleaner to help the cory heal. I think a wound or scratch became infected

Clean water I think will help most. With a good gravel vacuuming too. Debris won't help infection

 

[Burtle]

One of my corys have a strange growth on the side of it. I am not sure if it is a cut/bite mark, or a fungus. I am looking for advise.
I have a 20 gallon long tank, I switched to sand last week as one of my 3 corys died. I checked closer and there barbels are gone. I recently got 9 new fish all at once, so that may have caused a change. I originally had 2 corys, and 2 gouramis, I now have 6 coys, 2 gouramis and 5 Danio pearls.

pH 7.6
Ammonia 0 ppm
NO2 0ppm

The effected cory appears to not be that reactive. When I moved something next to it it wouldn't swim away. Eventually it swam to the corner and two other corys where swimming and pushed it trying to get food nearby. It rolled on its side then slowly got back up. Currently it is spending its time resting higher up in the tank. Any advise will help, Thank you

I would start doing some heavy water changes and dose with Seachem Prime. I suspect you may have some bacterial infections with the cories, and possibly also an ammonia spike with adding new fish. The prime and water changes will handle the ammonia, and also keep the water much cleaner to help the cory heal. I think a wound or scratch became infected

Clean water I think will help most. With a good gravel vacuuming too. Debris won't help infection

If my cory isn't dead now it doesn't have much longer, I think the new fish I got had some tpye of worm or bacteria with them. I'm not entirety sure, I eddited my post about further detail. thank you for your recommendation I have been doing water changes.

 

[Truckjohn]

Sounds like a parasite problem leading to secondary infection.

Quarantine treating incoming new fish is always worthwhile.

I would start a course of API General Cure + Erythromycin. If you still have corys or other bottom feeders in the main tank - treat the whole main tank.

Here's one recommendation for a treatment schedule:


Day 1: Water change then dose GC
Day 2: no GC
Day 3: Dose GC + EM
Day 4: Dose EM only. No GC
Day 5: Water change then dose EM
Day 6: Dose EM
Day 7: Water change and replace carbon in filter

 

[Burtle]

Sounds like a parasite problem leading to secondary infection.

Quarantine treating incoming new fish is always worthwhile.

I would start a course of API General Cure + Erythromycin. If you still have corys or other bottom feeders in the main tank - treat the whole main tank.

Here's one recommendation for a treatment schedule:


Day 1: Water change then dose GC
Day 2: no GC
Day 3: Dose GC + EM
Day 4: Dose EM only. No GC
Day 5: Water change then dose EM
Day 6: Dose EM
Day 7: Water change and replace carbon in filter

Thank you hope fully my other corys will not die.