mandarins are tough, most dont make it in home aquaria unfortunately. They almost always eat pods and you need alot of rockwork and usually a refugium in a sump below to supply one with enough and even then they may not have enough pods to eat. You can buy ORA ones that are about $50 where I live and they are supposed to eat pellets. The one I bought did not, it took a month of eating every pod in my tank before it would come around and eat frozen food. A few years later now and he does actually eat everything I put in the tank but especially likes new life spectrum small pellets. I think I got lucky, not sure I would try it again though, I stressed for that whole first month that I was gonna starve him to death. lol