Threadfin Butterfly Fish is Dead

Question
QUESTION: Dear T.J,

I had a 100G freshwater tank for more than 5 years and I wanted to switch to Marine tanks as every thing look much beautiful , right now I have a 75G tank with LR for a more than a month with powerful filter , UV and a PS , the LR had been put after they were cured by the LFS , I have 1 Royal Dotty back with one damselfish for 2 weeks and they are still doing fine , after 5 weeks of establishing the tank , I added two threadfin Butterfly fish to the tank , one was found dead after 3 days , the other one has just died after 2 weeks of putting it but with similar symptoms for the both , the BF was scratching itself the last three days with the LR a lot , but there was no symptoms of white spots on the body in both cases , some shivering in the head was also noticed , is it the Marine Ich ? I've read about the germs that cause this disease , how can I purify the water from these germs and kill them before they effect the other fish? If there are no symptoms right now on the other two fishes does it mean that they are not effected? Do I have to get rid of them even if there is no symptoms in order to get rid of this disease as these germs will die if they couldn't find a host ? What do you advise? I don't want to add more fishes until I'm quite sure these germs are out of my tank , one more thing , is the threadfin BF fine with the tank size? Was it the good time to add these fish to the tank or it was better to wait more ? If I have to wait what is the recommended time I have to?

Awaiting you helpful advice , and thanks in advance.

Regards,

ANSWER: Hey Sam

Yep, sounds like marine ich. The best way to prevent it is to quarantine any new fish in a spare tank for a few weeks. Adding a UV sterilizer to the quarantine also helps too. Ich can only attack stressed and weakened fish, so your other fish could be fine.

As for tank size, 75g is alright for one, but not for 2. Its best to add the fish after the tanks established for 1-2 years. i personally would get minimum 125g for them

---------- FOLLOW-UP ----------

QUESTION: Thanks T.J. for your useful reply , I'm thinking of adding some corals to my tank which has been running for more than 2 months , the water quality seems to be fine , the testing readings are quite acceptable , I'm also nearby the beach and I'm changing 10% of my water every 1-2 weeks directly from the sea is it a good action to do? In your opinion , what would be the time when it's ok to add corals ? And what kind of corals you do advise me to add as a startup?

Thanks and regards.

ANSWER: Ocean water is generally not recommended for water changes. Most of the time, pollution and other junk thrown in the ocean gets in the water and possibly in your tank, which you dont want

as for corals, what kind of lighting/how much wattage do you have? feel free to send me a follow up and i will name some corals

---------- FOLLOW-UP ----------

QUESTION: Hi T.J. , I have:

2 x 36W 10000k Fluorescent tubes
3 x 23W (100Watt) 6500K CFLs
1 x 16W x CFL (Blue color)

Do you advise to change to MH light? Or should I keep the same lights but modify the wattage?

Please advise regarding the light the type of corals I can start with , and the time I should start putting them.

Thanks.

Answer
thats about 160w of lighting. You would be limited to low light corals and non-photosynthetic corals, like mushrooms and kenya trees

if you can get a metal halide, its a good option, it gives you alot of coral choices. check ebay, thats where i got all of my halides for cheap.

if you want to ask me about a light or anything, feel free to send me a follow up