I have a lawnmower blennie and a mandarin in my 75. When I first got the blennie i had a ton of hair algae. The tank was very new then. After he finished it off, he would not eat anything else, he got very thin. I tried all sorts of things. Nori, algae wafers, frozen vegetarian mixes, etc.. I figured he was going to die, but then all of a sudden one day he just started eating flake.. Now he eats everything and anything and I have had him about 2 years. My mandarin is constantly picking at the sand and rocks, he has no interest in any prepared foods at all. I have had him about 1.5 years and he is happy and healthy.