Panda Cory discolor

[Zander2264]

Hello
I have a small school of panda Corydoras and slowly they’ve started to discolor turning white and becoming white. One of them has died and another is white right now. What is wrong with them?

 

[tanker]

Need more info. How big is the tank? What is you water parameters? How long have you had the fishes? Do you change water? How much, and how often? What do you feed them?

 

[Zander2264]

Need more info. How big is the tank? What is you water parameters? How long have you had the fishes? Do you change water? How much, and how often? What do you feed them?

I have a 20 gallon long tank.
Sponge filter and fluval aqua clear 30 hang filter
0 ammonia
0 nitrite and nitrate
ph of 7.4
~78 degrees (f)
I’ve had them for about three weeks now.
I change the water weekly between 15 - 30%
I recently did a heavy 50% to clear an algae bloom to get rid of the green tinge in the water but the problem started before that
I treat the tank with live bacteria after water changes and ph neutralizer when needed. (I test my water weekly minimum every few days while it is cycling)
They eat frozen bloodworms and a dry food. Photo below

 

[tanker]

I am concerned that your Nitrates are zero. It is impossible to be at zero with your water changes. I would get a better test kit.

Are there other fishes in the tank?

 

[fishorama]

tanker's questions & more. 78F is a bit high for most corys, most prefer low 70s. What other fish do you have that need (?) that temp? The lower range of our fish's can help increase their lifespans but can add to lethargy if kept too low.

I'm concerned you are (still?) using "live bacteria" & pH neutralizer. Is this how you're cycling the tank?