I have a black moor goldfish, plec and another different goldfish. We had a 25L tank that was smelly, bad water and it was too small. So we upgraded to a 57L.
We left this tank 2 weeks and added some bacteria to it. It also had plants in during this time. But I don't think it had adequate time to cycle (and my parents were pressuring me into moving them from the old tank because it had been left on the floor next to the new one). Anyways now the other goldfish is attacking the black moor (I think) the black moor has silvery scales that keep appearing and today was the first I have seen it attack.
I usually feed them at 5 each day so I put food in early to see if it was hungry it didnt eat and kept going after the other. I tried to disrupt the fight by gently waving the net near them. It carried on.
The black moor has also since developed a cloudy eye in both eyes. One is more milky white than the other. I tried using melafix. It didn't work after the week. So I did the weekly water change (25%) and stopped adding it hoping the cloudy eye would go away. Anyway I think it might be blind because it never finds the food when I put in and often surfs the gravel afterwards, eating and spitting it til it finds the sinking pellets.
The Nitrites are at about 3ppm according to this 5 in 1 API test and the general hardness is too high. I used one of those pillow to try lower the general hardness but it didn't go down after 7 hours ( I timed exactly how long to take from the packaging).
Finally I never see the plec eat. It never comes out at the time I feed and although I feed it half an algae wafer per day. I'm never certain the plec was the one who ate it and I am concerned it may starve to death.
I know this is a lot but can anyone give me advice and clarification on what to do because I really feel like I'm letting these fish down.
Unfortunately, there is little you can do apart from separate the fish or get a more appropriately sized tank The tank is much too small for two goldfish (minimum about 180 litres) and there shouldn't be a plec in there as almost all are tropical fish.
I would not worry about the hardness as goldfish do OK in hard water. The biggest concern is the nitrite - you need to change almost all of the water to get that down close to 0. Do you have a result for ammonia as that may be high too?
All that is in the tank is on advice from the pet shop of what we could have. I was much younger then so it wasn't really my decision. But since I've taken more responsibility for them I'm trying my best.
the fighting is new and has never happened before even in the smaller tank so it's really stressing me out. I have no way to separate them and I don't understand why.
They were probably only babies when you got them and have now matured. The goldfish is chasing the moor because either it's female or he thinks it's female and he wants to breed with it. They do tend to see any fish with a more rounded body as a potential female.