Is something up with my tank? Corycat white spots/open sores

[t_fish]

Hi,

I have a 30 gallon tank.

I noticed one of my corycats had a whitish spot on his back, I added some aquarium salt to the tank, today I noticed the spot was a full blown open sore. This afternoon he passed away.

I noticed a similar spot on another cory cat and one of my (i forget type, in the store it was in french Golden Chinese something?) seems to be fighting swimmer bladder which I have been trying to treat with Epsom salt baths for the past 3 days.

The water is 73 right now. I just tested it using the fluval test kit and all the levels are good according to the charts.
Ph 7
No2 0.1
No3 5
Ammonia 0.01

What could possibly be happening?
I dont use any water conditioners -- bad?

also the corycats are babies of the corycats we got. One apparently was a female and they had babies.

We've had this set up for a few months but am a newbie aquarium holder.

Any advice and suggestions is mucho appreciated!

[Aiken Drum]

Is there a reason for no water conditioner? Are you 100% sure your water is untreated? Open sores is consistent with mild chlorine poisoning.

[t_fish]

Originally Posted by Aiken Drum

Is there a reason for no water conditioner? Are you 100% sure your water is untreated? Open sores is consistent with mild chlorine poisoning.

Tbh pure ignorance. We assumed that because we were allowing the water to sit before pouring into the aquarium the chlorine would evaporate but clearly that system is flawed esp as I just learned "many water treatment plants have begun using chloramine instead of chlorine because it is a more stable disinfectant formed by combining ammonia and chlorine. Chloramine cannot be easily removed from water via evaporation and must be neutralized using dechlorinator." so maybe this or maybe we were too hasty with adding the water.

I will go out and purchase water conditioner. Thank you for the knowledge share.

[t_fish]

Also -- the fish with swimmers bladder -- after 4 epsom salt baths -- has survived and is back to swimming normally.

[Aiken Drum]

You should be able to find out if your water is chlorine or chloramine treated by contacting the water company.

Or do an ammonia test on your tapwater. If you detect ammonia its probably chloramine treated.

Water conditioners are always a good idea to use unless you are pretty sure you dont need it. They do other things than removing chlorine/chloramine. Take note, not every water conditioner removes chloramine.