Fish Breathing Fast, NEED HELP!

[rnb62679]

Hi there, I am having a big problem here and am not sure what to do... I have a 40gallon tank with 4 chromis and a small sailfin tang, and a cleaner shrimp.... My tank is about 7 months old and everything was perfect until about 2 weeks ago, I had to leave for a couple of weeks and the person I had in charge did not really do a good job cleaning the tank when I came back I had what looked like purplish algae. I am doing weekly water changes but my fish are breathing fast and one of my chromis stopped eating and is just staying in one place and not looking good...What can I do to prevent any from dying? My parameters are all normal.

 

[crister13]

Do a pwc. What is "normal"? Also, a sailfin tang needs a 125g, could be part of the problem.

 

[Sniperhank]

Wait...purplish algae? So you have coraline algae and are unhappy about it? Aside from that, everything sounds as I would expect. Tank is to small for a tang and as for the chromis...ok well that part doesn't sound normal. Sounds like they are stressed and it is possible start of ich? But, I can't see how a tank with a tang in it isn't stressed out just from that. He needs to go.