More than 100 fish were killed in Groudle Glen after a pollution incident during TT week.
The government says it's not clear what killed the 110 brown trout, but the source was identified as a surface water drain.
People are asked to take extra care of what they dispose of down drains, sinks and toilets.
The Department of Environment, Food and Agriculture continue to monitor the area.
Avoid Fairy Bridge after crash, say police
Man can sue DHSC over respite care PTSD allegations
More EV chargers at Sea Terminal?
Company warns over fake delivery emails
Should dangerous drivers who kill face life in jail?
Police dealing with crash in Colby
Stop falsely accusing youngsters of vandalising skate park!
Plans to make northern school more accessible