I have a 90 gallon live rock only tank. Plan on filling it with more then the 90 lbs I have more. I love rock. I have 2 clowns, porcupine and dogface puffer, foxface, panther grouper, and spotted hawkfish. I would like to add more. They are all medium to small sizes. But I prefer to only keep real hardy trustworthy fish. I would like to get a tang or two, and have had great success with Yellow Tangs before. Also would like a pseudochromis. I am open to all fish except eels. What fish would you recommend to someone who wants fish that frankly you cant kill! 5 out of 5 ins hardiness! Any ideas?