i have this ranchu, and there is this small white clear bubble on her back. also, it is surrounded by a small amount of what appears to be bloody tissue. her behaviour is extremely normal as is her diet and the conditions of the water. she lives in a 20 gallon tank. the tank has been running for like 5 months now. if anybody can educate me on the appearance of this bubble i would appreciate it greatly.
thank you
stacy
ps. four fish in tank, all the same size. quite small. i know overpopulated.

the fish also has one eye. but it has been this way for 5 months.

Hi Stacyy,sorry to hear that you're having problems. If you could try and answer as many questions up above in red as you can,that will so help as to give us an idea as to what may be going on with your fish.Any chance of a pic?