Roseline Shark Fading Colors

[Jsundrud]

I have 4 Roseline Sharks in my 75 gallon tank. Yes I know I should have at least 6 and do plan on getting more when everyone is healthy again. 3 of the 4 are totally fine and happy, but one has been slowly fading in color over the past week or so. Behaviorally he's fine - he's eating and swimming just fine, no gasping or anything either. Just the super faded color. I feed a mix of flakes, pellets, freeze dried shrimp, and fresh veggies.



I have treated the tank with a sodium chloride/malachite green mix as well as an antibiotic, but nothing seems to have helped. I was going to do a anti-fungal treatment next, but wanted to see if anyone had ideas of what could be causing this so I'm not subjecting my fish to unnecessary treatments.



I have other fish as well and the one lone Roseline is the only showing issues.


Tank Parameters:
dGH - 10
PH - 7
Nitrite - 0 ppm
Nitrate - 20 ppm
Ammonia - 0 ppm
Temp - 78

 

[StinkyLoaf]

You don’t need to be nuking the tank with so many medications (let alone the wrong ones). That’s a quick and easy way to make the problem worse or kill the fish. Likely why it’s not improving.

I like to encourage ignoring the “six fish minimum” rule.

Anyways, this particular fish could be stressed or not as optimal as the others. Is the lighting very bright? Is he the “runt” of the four roselines?

Dietary coverage is a key factor, but you seem to have that under control.

 

[Jsundrud]

I did want to stop medicating if it was something else or at least get a direction of what to use if it does seem like an illness. I definitely agree that subjecting the tank to unnecessary treatments is harmful!

I don't feel the light is bright but I'll reduce the brightness and see if that helps. They've been in the tank for a few months with no issues and nothing has changed as far as I know to cause additional stress.

He is the smallest one but they're all pretty close in size. None of them are significantly bigger or smaller than each other.

 

[Autumnsky]

Are these all males? Or do you know if you have males and females? How many of each?

 

[Jsundrud]

Unfortunately I don't know the sex of any of the 4.

 

[Autumnsky]

Well that would be helpful.

This post mentions in the "compatibility" section the smaller groups will antagonize the smaller, weakest one until death. it seems that others have had this experience in small groups of Roseline Shark /Denison Barb.
https://www.tropicalfishsite.com/denison-barb-barbus-denisonii/

 

[Autumnsky]

And the sexing part is similar for many other fish is rounder belly, broader front, female.

 

[Jsundrud]

Thanks for the article Autumnsky! There is one roseline who enjoys chasing all the other 3. Maybe they are harassing that one poor fish to the point of stress and eventually death ☹

I was hesitant to get more in case there was an issue, but I should be able to get to a store that has them in a week or so and I'll pick up a few more to increase the school size to see if that helps.