copods?

Mine are all over the glass when the lights go out. Almost looks like an infestation....

 

Hi
Try to train your mandarin to eat brine shrimp buy spot feeding him/her
I trained mine because I didn't have enough copepods Its been about a year
and he is doing great.

 

Pictures would be helpful seeing as there are so many types of critters in our tanks, it's hard to say from your description.

 

My Mandrian died.... im sure it was beacuse of the low population of pods!