Whats wrong with my goldfish fry?

Question

one of my goldfish fry (its still a very baby - only just started getting its colour) has developed swelling on one side of its abdomen (it looks internal). The fry seems fine, is swimming and eating fine but the swelling seems to be getting bigger - what could this be? I tested the water quality its fine - should i move it to a different tank? I'm worried about its brothers & sisters. Thanks!

Answer 1

could be worms  

Answer 2

it  could be something it ate my fish got that too and turned out it was   a rock  he swallowed it and   he    puked  it up    but in case its not something he ate i would put him into a diffrent tank just in case

Answer 3

Might be a internal infection or something. Sounds like dropsy. Dropsy is not a specific disease, but rather a condition where the fish's abdomen becomes swollen. It causes concentration of the fluids inside the fish. This results in swelling of the fish's abdomen. The actual cause of dropsy may be due to a wide variety of conditions. Its not very contagious but I would move it to another tank for treatment, Warm the temp to about 82-86 degrees .f and use epsom salts (1/8 teaspoon of epsom salts per 5 gallons) instead of aquarium salts because they will help the fish to lose some of the fluid that has built up.