White Skirt Tetra with red spot

[Riley4991]

Hello there, just looking for help as I haven't been able to find any online and could use some expert opinions on my current situation
I've got two white skirt Tetras, one has a red spot near the top of his top fin and the other has a very torn top fin and red along the edge of his injured fin.

I bought the tank online from someone who wasn't taking care of it and would never have allowed this sort of neglect, the tank has a very high amonia which I'm currently fixing with AMMO lock and a very high rate of nitrate. PH is off too. It's a 30G with 4 White skirt Tetras and one Glofish type and 2 Comet Coldfish which I'm currently trying to rehouse because they should have never been in a warm water fish tank or limited to a 30G... People suck

Also, I thought I broke the filter but you actually just have to add water to them (DUH! D So I have an extra 30G filter that I'm running on the tank beside the larger 40% functioning one that came with it, the currents not too strong in the tank I think. It's fine to do that to help clear out all this ammonia, nitrate and other gunk right? I'm going to do a full subtrate wash and transition over to sand when we're able to rehouse the goldfish, so I can limit the stress on the Tetras from moving around constantly. But until I'm ready to rehouse and do the full 2.0 to sand. (I've fallen in love with Kuhli loaches) That's probably the best thing to do right? (I've done the research on the sand, it'll be fine! Lots of washing.. Hours of washing)

Will do testing after I transition with my master test kit, but currently treating with the correct products anyways. That's fine for now right? I've just gotten into this hobby and this is a ton of issues for someone who didn't know what water conditioner was until two weeks ago

I think it may be some kind of internal bleeding on the Tetras, but that's my only theory... If anyone is able to provide information or what I should do to help them, it is much appreciated. I did read that the comet goldfish can be aggressive, but I have not see them attack the tetras at all.. Though they comb the bottom substrate all day so maybe at some point they are attacking out of desperation for food. I feed them a ton, but I notice the tetras rarely come to the surface to eat, maybe the comets bully them? The tetras don't seem very afraid of them generally

 

[Retired Viking]

If you have high ammonia you need to do large water changes 75% or so as soon as you can to lower the ammonia. Water changes is how you lower you ammonia levels. Make sure you treat the water with water conditioner. It will also lower you nitrate and nitrite levels. Cut back on the amount your feeding the fish that will also raise the ammonia level. Once you have done a major water change stop using the other chemicals like ammo lock and just do water changes with water treated with conditioner whenever you have ammonia. Do you have a test kit for ammonia?

 

[Riley4991]

Yes, I have an API Master Test kit. It came back at .80 PPM I believe, which is about double what I want. used the ammolock today and will do a full 75% in about 24-48 hours. I'm running a treatment for the goldfish and I just want them to be relaxed for a couple days, they kept trying to hide on me so I want to keep them relaxed and happy. cutting back on food too so the goldfish keep scavenging and release all those nasty chemicals in the water

 

[Riley4991]

I did a full clean and the tank is good now, everything is normal and I was able to rehouse the goldfish into a 700Gallon pond with 2 other gold fish as friends, very happy.

Still very curious about the spots if anyone knows? Is it a disease?