Red mark on Argentea

[seanh]

Have you tested your water?

Yes

If yes, what is your ammonia?

0

If yes, what is your nitrite?

0

If yes, what is your nitrate?

20

If I did not test my water...

1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

What percentage of water do you change?

61-70%

How frequently do you change your water?

Every week

If I do not change my water...

1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

A red mark has appeared on the side of my Argentea but not sure what could it be. There are no other symptoms, there doesn't appear to be any other marks and he is eating well still.

 

[Deadeye]

Could be an injury. In a tank with lots of cichlids there is bound to be fighting.

 

[MultipleTankSyndrome]

I think it might be the start of a bacterial infection brought on by high NO3.
Looking at all the threads about sick cichlids, even though I've never had cichlids, it seems like most come from water where NO3 is never higher than 5 mg/l. And if kept in water with a higher reading, they develop either acute or chronic diseases (depending on how much NO3 there is), such as bacterial infections or hole in the head.
My recommendation would be to at least quadruple the water replacement volume to get the NO3 down to 5 mg/l or less (for example, instead of 1 weekly 61-70% water replacement, 3 to 4 fin level 90% water replacements).

 

[duanes]

Nice female there.
as MultipleTankSyndr said it may be the start of a bacterial infection, or an injury as argentea can be quite quarrelsome, although it doesn't look like a big deal at this time.
M argentea come from flowing, "highly oxygenated" waters with very low nitrate, and pH 7.5 to 8.5.
If it were me, as MTS said, I'd up water changes to over 100% per week, in increments of 30-40% throughout the week to keep metabolites below 5 ppm.
Maybe you already know the gender differences, but
Here is a male.

the more vertical shaped forehead, and lack of melanin type markings
Again below, note the male in the foreground, with the longer fin extensions and lack of dark markings.

 

[seanh]

Nice female there.
as MultipleTankSyndr said it may be the start of a bacterial infection, or an injury as argentea can be quite quarrelsome, although it doesn't look like a big deal at this time.
M argentea come from flowing, "highly oxygenated" waters with very low nitrate, and pH 7.5 to 8.5.
If it were me, as MTS said, I'd up water changes to over 100% per week, in increments of 30-40% throughout the week to keep metabolites below 5 ppm.
Maybe you already know the gender differences, but
Here is a male.
View attachment 1501161
the more vertical shaped forehead, and lack of melanin type markings
Again below, note the male in the foreground, with the longer fin extensions and lack of dark markings.
View attachment 1501162

Thanks, the marks seems to be clearing up after increased water changes. Interesting that I have a female, I was sure I had a male! Nevertheless, lovely fish!