Lump on Ram

[Shushan]

Any idea what this lump could be and treatment? Water parameters all fine ammonia 0 nitrite 0 nitrate 20ppm, tank set up for about a year with 50% weekly WC.

 

[Colin_T]

How quickly did the lump appear?

It looks like a scale that has lifted and is covered in mucous. The fish might have injured itself and lifted the scale. If it is a scale, then maybe add a bit of salt and monitor the fish.

Salt, use 1 heaped tablespoon per 20 litres of water. If there's no improvement after 48 hours, increase the dose to a total of 2 heaped tablespoons per 20 litres. Keep salt in tank for 2 weeks.