Help Missing Siamese Fighter Fish And Dead Apollo Shark

[Ginge2010]

Hi i switched my tank on this morning and noticed my siamese fighter fish is missing and i found my apollo shark dead behind my filter the shark showed no sign of illness and was swimming normally last night before i went to bed i checked the fish for anything unusual and theres nothing there iv not been able to check the waters yet i will post results asap.
The fish are fed flaked food blood worm garlic catfish pellets and algie waffers obviously not all at once lol

 

[the_lock_man]

When you say that you switched your tank on, are you talking about lights or filter?
 
A set of water test results will help greatly.

 

[Ginge2010]

The lights my filter is on 24/7 il do my water tests as soon as i get 5 minutes to do them