Who Gives A Fish Forums

I'm at a loss with this lump - anyone have any ideas what it could be and what the treatment might be? My water parameters all look good - 0 ammonia, 0 nitrite, and 20ppm nitrate. I've had the tank set up for about a year now and I do 50% water changes every week.

I'm curious, how quickly did you notice this lump on your fish? It's possible that the scale got lifted due to an injury, and that's why it's all mucousy. Adding a bit of salt might help - I'd recommend starting with a small dose, about one heaped tablespoon per 20 litres of water. Monitor the fish closely and see if there's any improvement after 48 hours. If not, you could try increasing the dose to two heaped tablespoons per 20 litres. Just be sure to keep the salt in the tank for a couple of weeks to see the full effect.