Please help me

[reeferlover]

i have a 75 gal tank setup

its not that mature but has cycled and the rock was matured in a tank before setting the tank up

all parameters are in check and my corals are doing amazing

all fish are very healthy looking eating anything i put in the tank.

so my dad got me a nice small to med desjardini tang. he was looking great hid a lot but after two days he started coming out and picking on my rock work. the next day gone. no body no parameters changing nothing gone. he made it 3 days

next my sixline has no dissapeared. he was in the tank for about a month. the last time i looked at him he was fat and healthy awesome looking fish. gone no body nothing

now my firefish 6 weeks in the tank fat health probably over fed lol gone no body nothing.

i have checked all over the tank that i can see all over my floors everywhere. what is going on any ideas. im really worried no fish ever showed any signs of disstress or illness

 

[falconut]

From the minimal information, it could be some sort of preditor, like a mantis shrimp.

 

[DustyReefer]

Agreed could be a predator, if its a RR 75 check the overflow, you'd be surprised. Other than that nothing really comes to mind. Very strange... Keep an eye out for them to see if any pop back up. Fish can hide extraordinarily well when they don't want to be found.