DaveA76
Fish Crazy
2 weeks ago i bought 2 2" severums for my 240L roma, they are getting along fine with tank mates but in the last 4 days they have developed black marks along there backs, all the water parameters are fine as ive been testing every few days to make sure they are fine and i do a 50-75% water change every week depending on how much time i have to do it, could anyone shed some light on what it could be ?