I hope you are able to keep him fat and happy. That is a TINY tank for a mandarin and being an AIO, there is VERY little room for copepods to populate. Try training it to live brine and then to frozen brine and finally frozen mysis. This can help save you A LOT on feedings. It can take a good while, but is well worth it IMO.see i was thinking that way...its happy but i dose everyday and well well established a month prior...its only a 12g all in one...for now