For several months now I've noticed a little whitish/greyish dot in the centre of either eye of two of my fish, both White Cloud Mountain Minnows, both towards three years of age now. I have another younger White Cloud Mountain Minnow, and after taking a close look, he doesn't appear to have the same issue.
Obviously this could be a number of things such as water quality, bacteria, age or vitamin deficencies: I don't believe there's any bacterial infection going on, and I conduct a 50% clean once a week. I last tested my water prior to last weekend's 50% change, and my parameters were all great - nitrates are 30-40ppm (but they used to be far higher than they are now, and I intend to keep it that way) and Total Dissolved Solids were coming in at 305ppm (steadily creeping up over the course of three months - back in March/April, I was looking at 230-260ppm). The water quality used to be worse due to me previously having unsuitable fish in the tank (Clown Loaches), so that may have had some bearing on the present issue (I had been registering trace amounts of nitrite after feeding, for instance). Currently it's just these three White Cloud Mountain Minnows.
The only parameter that I have limited control over is temperature. Heater is unplugged, but with the tank light on 7 hours a day from 2pm-9pm, the water reaches 24-25C, and has been holding around 24C while the weather has been warmer (ambient room temperature not as low as it was earlier in the year, so even when the tank light is off, the heat will be radiating from the water slower). White Cloud Mountain Minnows being cold water, this isn't ideal, but I've done what I can (I've decided not to opt for LED lighting for the time being).
If vitamin deficencies, I could try feeding live food to vary their diet - at the moment it's flake food every other day, swapped with de-thawed, de-shelled pea once a week (not blanched, I just defrost and cut/mush the pea up). I haven't fed live food in over a year and a quarter - it was April last year - so it might be a good idea to do so soon.
Obviously this could be a number of things such as water quality, bacteria, age or vitamin deficencies: I don't believe there's any bacterial infection going on, and I conduct a 50% clean once a week. I last tested my water prior to last weekend's 50% change, and my parameters were all great - nitrates are 30-40ppm (but they used to be far higher than they are now, and I intend to keep it that way) and Total Dissolved Solids were coming in at 305ppm (steadily creeping up over the course of three months - back in March/April, I was looking at 230-260ppm). The water quality used to be worse due to me previously having unsuitable fish in the tank (Clown Loaches), so that may have had some bearing on the present issue (I had been registering trace amounts of nitrite after feeding, for instance). Currently it's just these three White Cloud Mountain Minnows.
The only parameter that I have limited control over is temperature. Heater is unplugged, but with the tank light on 7 hours a day from 2pm-9pm, the water reaches 24-25C, and has been holding around 24C while the weather has been warmer (ambient room temperature not as low as it was earlier in the year, so even when the tank light is off, the heat will be radiating from the water slower). White Cloud Mountain Minnows being cold water, this isn't ideal, but I've done what I can (I've decided not to opt for LED lighting for the time being).
If vitamin deficencies, I could try feeding live food to vary their diet - at the moment it's flake food every other day, swapped with de-thawed, de-shelled pea once a week (not blanched, I just defrost and cut/mush the pea up). I haven't fed live food in over a year and a quarter - it was April last year - so it might be a good idea to do so soon.
