Red Gills?

[Justaerin]

Hi all

Noticed that one of my corys had gone a bit pink round the gills last night and now its spread to a couple of others in the tank too. They've also developed rather shiny patches that cover their sides from infront of the gills to about half way down their bodies.
These are new additions to the tank. Also quite lethargic.
Any ideas what it is or likely causes? Will be doing a water test in the morning along with a minimum 50% water change before popping into the shop where I got them to see if they have any ideas or treatments.

Thanks

 

[KISSfn]

Is your filter cycled? You should test your water now. The shop will probably try to sell you something you don't need.

 

[Justaerin]

It should be, got it all second hand from someone I know who had it running and it only wasn't running for two hours. I've had the tank set up and running for a number of weeks with no problems. Water checks were fine.
Could it be that the filter hasn't caught up with the new increased bioload? and would daily water changes help?

 

[KISSfn]

Size of tank? All inhabitants? What did you test water with? Ammonia and Nitrite zero? How did you acclimate new fish? A large water change is always a good thing.