help my mates red cap died

[red-devil0602]

my mate has got a new cold water set up, she has let it mature etc so i took her to get some fish yesterday. she got 2 redcaps one of which was dead by this morning and the other has white stuff on his redcap. the water was fine but today it really stinks and has gone cloudy. any ideas what is wrong

 

[WILDER]

How big is the tank, are you running a filter, Where is the redcap on the body, is it fluffy in appearance.

 

[black angel]

redcap is a type of oranda with a red hood or wen. Has your friend tested the water yet for nitrites, ammonia, nitrate and ph yet? how long has the tank been running for? Maybe the filter hasnt matured enough to cope with any fish yet or putting two in was too much for it.

 

[bribones]

for a fish to die overnight can only be one of a couple of things ,toxic shock or damage during transit if the fish seemed fine at purchase id check the stats of the tank