A 75g is a fine tank for a small pebbletooth eel like a snowflake, skeletor, or banded. These eels don't necessarily eat fish if they are sized properly from the beginning. Dwarf and medium bodied lions would be safe with any of these eels. Dwarf and medium bodied lions can be challenging to keep long term, if you are interested you can click my name and "find all threads" to find tons of information on keeping lions. A marine betta, small tang, and dwarf angels are good additions to a predator tank of this size. Some people like to add a Canthigaster genus puffer to a tank like this; the blue spot tends to be very nippy and I would not trust with my lions, while the saddle and leopard tend to be better behaved.