What's a live food I can breed for moray eels?

I have two morays that have been on hunger strike for a while. I thought introducing some live food might make them happier. One of them recently ate a green chromis I had but I'm not surprised. Any ideas on what would be a good treat for them? I'm worried that they're bored. Oh they are Indian mud moray or gold dust moray. 
First, it does better in brackish water than a pure saltwater environment. It's also nicknamed the freshwater moray eel. It breeds in freshwater... 2nd it has poor eyesite like most moray eels. It's a scavenger so dead food. I used to feed my Zebra frozen krill that I let defrost in a bottle of water. Then I'd turn the bottle upside down and he would swim in and eat all the krill. If I put my hand in the tank he'd brush against it - like a dog wanting to be pet... I found a website that can legally sell mangroves. I recommend a lower salinity system with mangroves... 
I already feed krill. But from my research the freshwater moray starts off in fresh water and relocated to a full marine environment. 
They do relocate to a marine environment but throughout life return to freshwater. I've been told (amazingly) eels are social creatures and tend to do less well when not interacting... And you are saying they aren't eating the krill?
I have two in the tank and they are good buds. And not much. Every now and then they will take a nibble. I'm thinking they are eating at night. I used to tong feed them but they refuse to accept that now. Maybe I will put them in a tank with slightly less salt for a bit and see if that helps. I have a few marine fish in the tank with them so I can't decrease the salinity too far. It's at 1.023 now.  I have had them both for about a year now so maybe they naturally want to return to freshwater for spawning? Might be a good time to try to breed them I guess xD
Sexual maturity causes a range of problems in all creatures, it could reasonably cause the reduced appetite... Possibly
Lol I posted this about 6 months ago. I upgraded them into a 150 and added a sump. They're eating fine now. They are best friends, they have tons of caves but always prefer to cohab. Mud morays are not solitary