I went to feed my fish in the 90 litre a short while ago, it currently houses 11 wcmm and my 4 hsl (mum, dad and the 2 kids). I noticed that my small hsl has a pink area on its back, i presume it has either scaped it against the tunnel, or could it possibly have been attacked by another fish ? all seems peaceful in the tank though.
Do you suggest melafix / pimafix ? I have them both in. Am I ok leaving the little guy in the 90 litre (bit worried about moving him out on his own, they like company I think and he has always been with his family).
I have worried about this one for a while, he is considerably smaller than his sibling - just seemed to have stop growing. he has always been a lively chap though and constantly grazing on food (as they all are). We often hear dad swishing his tail in the gravel (no more babes produced though), and I just wonder if that is territorial - warning the little man off.
Fishkeeping since April 2010 (still loads to learn )
It looks like a clean wound (no fungus/fluffiness) so I would try Melafix on its own to help it heal.
The cause could be an accidental knock/graze, heater burn or more likely, if the injured fish is male, his Dad is bullying him. This species do demonstrate superiority and fight by getting on top of their victim. Possible his small size is because he's stressed by his Dad's attacks.
Well it might sound counter-intuitive, but one solution if tank footprint and stock level allows would be to add a couple more youngsters. Dad may well spread his aggression around a group which will lead to less damage. Also, if you're aware that Dad has a favoured grazing area or resting place that the youngster invades, a rearrangement of decor with clearer territorial boundaries may help.