I had a mandarin living in my 20 gallon for 2.5 years.

It eventually took frozen so was good for me.... and I never ran any type of fuge.

On a side note.... let the tank mature for 6 months minimum to allow a build up of your pod population and avoid adding anything else that may feed on pods. Pod eaters are common in tanks... such as sand sifters, so choose fish wisely.

I was planning to let the tank mature and I know lots of people that have had success with mandarins in 40 gal tanks so I'm not worried about a mandarin cleaning out all the pods.

Still looking for advice on sand or no sand in a fuge area.

same question.... I made a refuge out of an aquaclear 70 and not sure what to put in it to sustain and produce pods for my mandarin....