1 clown fish dead one not looking to hot

[FishypantsMitch]

I am new to this saltwater fish thing and I put two clowns in a fluval 13.5 and they were black and orange but are starting to turn white I’m not sure what happened to them. Also there is some brown stuff growing on my rock also not sure about that

 

[Areseebee]

Can you give more background about things like:
1) how long have they been in the tank?
2) how long has the tank been up and running?
3) did it cycle? Did you test for ammonia?
4) How did you introduce them? Acclimation procedure

 

[Jon Fishman]

Water parameters? Got some Ammonia in there?

 

[FishypantsMitch]

Can you give more background about things like:
1) how long have they been in the tank?
2) how long has the tank been up and running?
3) did it cycle? Did you test for ammonia?
4) How did you introduce them? Acclimation procedure

The tank cycled for two months they have seen in the tank for 4 weeks tomorrow ammonia is at 0 and I dripped acclimated then for an hour

 

[FishypantsMitch]

The tank cycled for two months they have seen in the tank for 4 weeks tomorrow ammonia is at 0 and I dripped acclimated then for an hour

And there is only one now the other one died yesterday night

 

[FishypantsMitch]

Water parameters? Got some Ammonia in there?

No but the one is turning white could it be a disease