well this tank isnt really mine yet... its my parents but they are giving it to me, thats why it isnt in my profile. There are only four fish, we have had these same fish for about a year or so. (this means no new fish have been added). The tank's quality (ammonia, pH, nitrites, nitrates) are fine. We have two power filters in the tank. These fish are big, but they arent really that big compared to the size of the tank. There is still a lot of room, and there is also a lot of room if you go by the "inch-a-gallon rule". I always say that one goldfish should get at least 10 gallons. So this leaves 35 gallons left over. This tank is a very clean tank and it is in good condition, which is why i am confused that this fish has a cloudy eye. I really hope this helps you guys out.