i would not recommend a lawnmower blenny unless you have a lot of algae in the tank for him to graze on all day. they eat all day long. it took mine a long time to finally eat the herbivore flakes i was offering as well. ocean nutrition formula 2 flakes. mine loves green hair algae the most. a lot of them will starve to death without lots of algae growing in the tank. also remember that a fish needs to be eating well in a pet store, not just eating some of the food offered. trying to save an unhealthy fish a lot of times doesn't work. they should be fat and eating well in the store. if a store won't feed the fish in front of you, find a store that will. bicolor blennies are much more likely to take to other foods such as ocean nutrition pellets, flakes, frozen mysis, etc. if you need to keep them alive while they take to another food, feed live brine shrimp. and then you can also add frozen brine shrimp. a blenny should always be fat. and really any fish should always be fat.