Originally Posted by Sniperhank
I'm not aware of any trigger that would be able to live a healthy and long life in a 55. They simply get too big and are 100+ gallon tank fish.
Dwarf lions, like the fuzzy for example that doesn't get larger than 7 inches, might stay small, but if you have two on top of an eel you will run into parameter issues without some heavy water changes or skimming.
I guess I'm spoiled because I have always had means to re-house fish when needed, so I tend to be more forgiving when it comes to stock selections.
as far as water parameters are concerned, that is why I stated "if you know what you are doing" and that the full on carnivores like lions, eels, groupers, etc., can easily get by with being fed only once a week-10 days.
also bear in mind that those critters are much less susceptible to issues with nitrate than are corals and inverts. I fear far too often folks chase numbers that for all intents and purposes are very difficult to achieve unless you either have very, very minimal stock or essentially starve your animals.
It also depends on what the person desires for display aesthetics. If they want a specimen tank, then that size would be fine for a pair of dwarf lions and an eel or three, but it would require diligent maintenance practices on the part of the hobbyist.
If they desire something more "natural" then of course you want smaller fish that do not look out of place relative to the tank/décor.