Anyone know silver dollars?
Welcome by the way. I’m virtually a beginner so no use to you whatsoever but best of luck.
You could try inputting Silver Dollars in the search function top rightish of the screen. It’ll bring up nigh on 20 yrs of Silver Dollar related questions, answers, debates etc. Maybe something helpful will be there.
You need to start with your water, have you tested it for ammonia or nitrites? When did you do a water change? I would do a 75% water change to start with to flush the systems. I have had a few silver dollars a long time ago and I think they tend to be sensitive to water chemistry . Did you dechlorinate your water the last time you did a water change?They are also very sensitive to chlorine.
Are you sure that’s a silver dollar? From the way the picture looks it looks kinda like a small pacu or peranha. I also have to agree it does look like a older fish.
test your water for ammonia, nitrite, nitrate and pH.
do a 75% water change and gravel clean the substrate every day for 2 weeks and see how it goes.
make sure any new water is free of chlorine/ chloramine before it's added to the tank.