I have a dwarf neon rainbowfish which suddenly developed a whitish pink lump on its side, it is raised and i initially thought it was injured and treated for possible fungal infection. A week later it is no better and tonight looks like the lump has burst with all white strands hanging from it. The fish appears well in itself eating swimming and brightly coloured. I have spent hours trying to look up what this could be but am getting no where. I have another 5 rainbows which currently are fine along with all other tankmates. Please could anyone shed some light on this for me so i can work out how to proceed.