Cromis cause mass death???
 

3 foot tank - 120 litres
2 clowns
1 blue stripe cleaner wrasse
1 humbug damsel
2 green chromis

Up until today, 1 royal dottyback

1 year old tank
Ammonia = 0
Nitrate = 5-10
Biolife filter

I got 5 chromis the week before Christmas. I lost 3 within a week. This morning my dottyback (1 year old) was just dead on the bottom of the tank with no prior warning.

Now my humbug is looking really lethagic, not eating (I don't think he's eaten anything for 24 hours).

One of my clowns, the female, has what looks like a pimple on her chin. I've been using some fishy medicine periodically for this for about 2 months and it comes and goes.

Any ideas what is causing my tank to suddenly be so sick when I haven't had any fatalities in the year its been operational?

steph