Tank Problems!!

Does anyone know what this is? I also think my fish have ick. Two have died in the last two weeks.

 

What are your water parameters?
What type of filter and gph?
Current stocking?
Any new inhabitants?
Lighting schedule?
Are you dosing anything?

If you can answer these maybe we can help. Hopefully a salty will.

 

Not sure at the moment what the parameters are. Marineland 350 penguin 800 gph. Yellow tang, two clowns and two basslets. One basslet and one clown died. No new inhabitants and no dosing

 

It's could be your live sand growing bacteria it doesn't seem to be on any of the live rock it's a long time since I kept a marine aquarium so maybe someone with more experience might know more

If you don't test your parameters it could be anything killing off your fish

 

I would need a lot more information before I could possibly help:
- Is your tank a 20g?
- What are the ammonia and nitrate reading?
- Why do you think your fish have ick?
- How long had you had the fish? (Yellow tangs need at least 100 gallon tanks so if he makes it you should re-home him)
- What is your water change schedule?
- Do you use RO/DI water with salt mix for the water changes?
- Are you using RO/DI water for topping off?
- What is the salinity?
- What are you feeding?