Put it this way, I had an arowanna that grew to 4'. So you tell me if that can go in your tank with those fish. Possibly will eat the other fish besides the Pacu.
I believe they are freshwater, but I wouldn't put them with africans cause of there size. Go to website called the age of aquariums, they have some info on puffers. Theres a better site but can't think of it right now.
Have you put your hands in the tank at all. If anything was on your hand, even small amounts of something could leach into the water and kill your fish. For ex. cleaning your kitchen counter with some kind of spray and then later doing something in your tank. If I do anything, I wash my hands...
I take my last post back, and I might be on the money by saying it is a Pseudotropheus Saulosi(female). Try doing a search on that and see if that looks like your fish.
A razorblade should take that right off. I bought one with a long handle for my 150g. I also use it to clean the glass from all that crud that builds up on the under side of it. I think it's your best bet.
Giant Daniels are great for the top and are very active. They keep your other fish moving. Also for color you can try Rosy Barbs, also active and are a bright orange/red.
How long before the tank would run out of oxygen if there was no power. 125g. tank ex. 25 fish. How long could they survive. And are there any ways to add oxygen to the tank without power. Thank you