Gourami Hole In Side

[MRFANTASTIC148]

So I noticed this morning that one of my gourami has this huge hole in its side. I’m thinking it’s a parasite or rot.
I work nights so I decided when I woke up I’ll go get some medicine for the fish since the fish store wasn’t open till 11. Well when I woke up I notice it was worse.
So I separate the fish from the others. (Didn’t think you do that at first because thinking of its a parasite then the ready are infected as well) And I am now thinking maybe one of the other gourami has done this.
It’s a very bad wound, but it is eating and I’m hoping it can heal and be fine. Has anyone else have gourami do this? Nip at one fish this bad like eating them?
I’ve also have had a lot of other fish just randomly die for no reason. When all my chemical levels are good and everything fine.
If I’m correct this is a female. I have two other females and 3 males but as far as I could tell there was no fighting.
I have them in a 125 planted aquarium.

 

[Autumnsky]

Do you have a test kit to check the water ammonia, nitrite and nitrate?

Having the water be in tip top parameters /safe level is the best way for fish immune system to be able to deal with the n=medical problems /healing.

When was the last time you have done a water change and how much did you change out of the 125G?

If it was around a 25% pwc with in the last week or 10 days, I would recommend doing 2 back to back water changes of 30% change 30%, then change another 30%.

It makes the difference in the new and old tank water less stressful on the fish.

If the water change has been longer 2-3 weeks, then I would do a 2 - 20% back to back water changes. Wait at least 8-10 hours and then do another pwc maybe a 25%.

If it has been a few months then do 10% back to back, then another 8 hours same thing, and then repeat a 3rd time.

Having the numbers of the parameters are needed to make sure everything is in the safe level.

Also important is to check if it could be a burn from a heater. Maybe a spot it could get stuck?

A wound can certainly become infected and cause this type of injury, as could some other type of serious parasite infestation.

Do any other fish seem to have any injuries, red spots, worms around the eyes, gills, body, anal vent? They could be super tiny. Are they flashing/ rubbing against items in the aquarium?