I am sort of 'new' to marine - about 3 year now. My first 'monster' was the biggest Angler/Frogfish I have ever seen at a Petshop - about 9 inches. The only thing I could mix him with was a Lion fish, but he started showing some interest in him, so I decided to get rid of the angler before he ate my lion. Problem with keeping monsters in marine tanks is this: it is SOOOO hard to find another fish large enough to stick in with them, unless you are thinking of getting larger angels (most of the time, they won't eat if you buy them over a certain size).
Eventually I moved on to Morays. Bought a Fimbriated moray. Morays are horrible when they attack - they just won't let go. I blame myself for this little 'incident'. I had a 7 inch convict blenny - TERRORIZED the fimbriated moray. The moray was only 9 inches or so, but thinner. One day, I was feeding them pieces of shrimp. Two pieces were falling down. Moray came from behind the rocks, perched up, and kept looking side to side at two different falling pieces. The convict blenny moved in on one of them, and the moray must have seen some 'movement' and just striked. Caught the Blenny right behind the head, and pulled them blenny back behind all the live rock. I immediately tried to get a 'stick' to seperate them, but the moray had his body wrapped around the blenny (very similar to what a snake does). I then lost sight of the two of them again. About 5 seconds later, I saw the outcome - a decapitated convict blenny. I know the moray was not strong enough to bite through the blenny, but with it's tugging and biting combo, eventually popped the head off.
Morays have HORRIBLE eyes, and you need to pay attention when you feed them. They will snap without really knowing what they are snapping at. There was NO WAY the moray would have tried to eat the blenny.
I spent quite a long time looking for a Honeycomb moray. Gorgeous eels - second only to the Hawaiian Dragon Eel pictured above (will post my pics in the next few days of my pet). Eventually, somone traded their's in. Bought a 2 foot specimen, and with a good girth on him. Put him in with a 5 inch Pink Tailed Trigger and a 5 inch Porcupine Puffer. About 5 mths later, he took my trigger. He grabbed him sideways, pulling him through the expanse of live rock I invested in to make him comfortable. I have huge pieces of rock, and he pulled that trigger sideways through all the rock, moving 25 and 30lb pieces with ease. I took my net, and tried to 'choke' him into letting the trigger go, so I can at least stick him in my sump and bring him to the petshop to trade him, or just give him away at least. Didn't work. I tried using a stick..eventually just pushed his way through it. So strong! Saw him gulp him down
Every feeding time, he started taking a bite at the puffer. Puffer would blow up in his mouth. No way he could get him down I thought. Even if he doesn't blow up, the puffer is simply too wide to get down his throat - dislocating his jaws or not. Puffer showed no worse for wear, and he grew another inch and a half. Unfortunately, the eel grew another foot - just over 3 now, and THICK from the 2x/week feeding of 4 large sticklebacks, 1 large squid, 2 small sized octopi and 3 or 4 small anchovies - plus all the shrimp, scallops and everything else he 'stole' from the puffer.
One morning, I turn on the light, and the puffer was gone, and the eel had a fat stomach (and I swear, a smile you just knew came from winning).
Got rid of my eel 3 weeks ago now
By far, the easiest fish I have ever kept either fresh or saltwater.