They're awesome, definately one of the best of all aquarium fish. They love woodies and mealworms, and they're not going to cause the fish any trouble. Whole, live invertebrates are ideal food, they're quite natural. Processed fish food is okay. I could never understand why fish people used to use ox heart so enthusiastically. It's no better than any other cut of meat, I suppose it's just a bit cheaper. Mammal flesh isn't a natural food and isn't a good staple for them, but it's good for a treat. Mice are good too... I can't recommend it, but I've known a few people who fed theirs live mice. I used to catch Gambusia (small noxious fish), which they'd eat, although they had a bit of trouble catching them. I used to feed mine all sorts of things, including a lot of dog food. If I was keeping them now I'd give them mainly fish (preferably small, whole fish), woodies and mice (dead), as well as whatever else I felt like once in a while.
I've never heard of them liking brackish water, and I would be cautious about trying it.
I tried to train mine to ring a bell for food. When I went near the tank they'd swim up wanting food, knocking the bell around, but they'd have been madly swimming in that area anyway
Looking back at it now, I didn't do a very good job of teaching them
