[the_dankinator]

Hey all. I currently have a few Monos (5) in a 20 gallon tank (don't worry, they are little, and will be moved when they get bigger) and they, along with the plants and Bumblebee Gobies in the tank, are all healthy, except for one. It has these white patches all over one side of its body that look like scars or itching wounds, but there is no sign and there was never any sign of Ich in the tank. The fish have all been in there for a few months now.

My first assumption was that it was by cause of fighting because they occasionally get aggressive, but only to chase one-another. The amount of scarring didn't add up to this guess, so after looking at some other forums, I decided it was a problem worth asking about.

Other than showing signs of scarring, this fish has been eating enough (as far as I can tell), swimming around, and not necessarily acting different than the others. This is a mystery to me.

I've been doing regular water changes every 1 1/2 to 2 weeks, as well as testing the levels of ammonia, nitrate, nitrite, and pH with no noticeable issues. The salinity is currently around 0.04, as I am trying to go towards fresh from brackish to introduce algae control. The pH lies at around 8.2, thanks to Flagstaff water, but this isn't much of an issue considering the ocean's salinity is about the same and these are brackish fish. I am using a DIY CO2 system with a couple two-liter bottles and a diffuser, but I don't know if this would have any sort of effect on the fish. The last time I changed the water was yesterday, and all levels are currently normal. Any ideas? Also, are there any ideas for how to reduce aggression with these fish? Or is it just their nature?

Update: As I am writing this thread, I noticed that there is a recognizable sign of illness! The fish has a sticky string-like waste trail (small, but noticeable), so it could be overfeeding, which I doubt, or some kind of infection.

Thanks for the help!

 

[blackandyellow]

Its difficult to help diagnose without a pic, but one guess is that it could be a fungus that set on after an accident. Your best bet would be to treat your whole tank.

Monos are schooling fish and you need to keep them in a large school. They grow quite a bit and will need ASAP a large tank, a 20 gallon is too small even if they are still small, as they are fast swimmers.

These fish as you know need brackish water when they are young, and fully marine water when they are mature, so they are not suited to planted setups

 

[the_dankinator]

Today, it has started looking like more of a fungal infection, so that's probably what it is. I am aware of their need for a larger tank; they are being transferred in May, so I'm sure they'll be fine until then. Fortunately, I already have everything I need to treat fungus, so we'll see what happens in a few days. Thanks for the feedback.