Thank you!
There happens to be salt in the water 2tsp/G because i am treating ICH. also for that reason the temp is about 90, which they seem to love.normally I keep it at 86.
the last visible ICH was about 6 days ago.none of the fish were visibly stressed by it.
I have 5 individuals in a 20 G,. with lots of driftwood and rock cavey places and plants.
Two of them have been in there for about 2.5 months and the other three about 2.5 weeks.
I have seen only very mild agressive behavior and not targeted toward any particular individual. That I had noticed.
There seem to be Two fish (I am not sure which gender

,)Who will occassionally sort of flare and dart at the other fish. I have never seen them make physical contact. The other fish will swim away and the agressor doesnt follow. One of these two is more agressive than the other only in that s/he will also occassionaly chase of the other chaser. if u see what I mean.
I was sort of thinking it might be some sort of dominance hierarchy deal, but wasnt too concerned about it. Everyones color apetite and activity level has been very good even through the ICH. The new fish had bad color for less than a day when I added them, then colored right up. The Pushy' fish are One original one and one new one.
To be honest I don't know the exact ph. I know that mine is the same as the ph at the store (The Fish Place) where I got them. Each week I do a 10 gallon water change and use 8 gallons of tap water and 2 gallons of RO water,(as per Nataku Tseng's advice)
So I "figure " it is soft and acidic enough. I will have the PH tested tomorrow though. On this tank AND the hospital tank.
The fish had been doing very well until a new acqusition brought in the ICH.
The injured fish is one of the new ones..
Ive been watching him carefully all day. He doesnt look at all well. He was staying in one place and the other fish appeared to 'visit' him. lol
I was watching very closely to see if he was picked on at all, but he wasn't. One or two fish would just seem to hover near by for a while, look him over, then swim off. It didn't appear to stress him any further.
At one point he moved to a corner were he could be alone for a while, but after an hour or so, Voluntarily left the hiding place and rejoined the community! even though he just sat in one place some more.
So, I really don't understand unless, maybe.. could there have been some sort of breeding thing going on at night that involved an attack?
I read in One place that introducing salt water can induce spawning ( but then i have read some odd contradictory info about these guys)
I turned off the light to try to reduce stress as much as possible,but...
Any Chance there is agression that only happens after lights out?
Thank you all for your help and for reading all this.
I wish there were more I could do for him.