goldfish

[gizmo851]

i have 50 goldfish in my 2.5m by 2.5m by 2.5ft deep pond with oxey plants pump and uv filter but acouple have red blood marks on there side can you please advise

[maggie01]

Sounds a bit overcrowded.

[heathfield]

Does sound a bit crowded. The reddening could be 'Costia', (or not). See here for that and other general goldfish health problems