corydoras

Hi I'm Thomas 3 months ago I've started to work in a two PetShops in South London - UK Just couple days ago, did set up my first tank - never though like I will go into Aquatics... Of course I try to read and learn as much as possible.. but mistakes are done already. I have problem with Ph in...

So I bought 4 new Corys (pretty sure the shop advertised them as Corydoras sp. columbia). And the past few days one in particular has been looking off - paler than normal, and noticeably smaller in size than the others. Yesterday when I looked in the tank it looked dead - was upside down on the...