[jtbadco]

There are a few things you can do to assist with getting Mandarin gobys to thrive.

First, having alot of good intricate LR in the DT is essential. You need lots of little cracks and crevices for the copepods and amphipods to reproduce in.

You can assist this with little 'rubble piles' located throughout the DT as well.

You can also build a small 'cryptic tank' or sump/refugium above the tank and gravity feed the return into the tank.

Also, adding some type of small live foods to the tank may assist in stocking it with lots of Mandarin food (ie Tigger pods, etc)

I also suggest looking into ORA captive bred Mandarins. They are raised on prepared foods so are more likely to thrive in a home aquarium.

There are probably lots more things that more experienced reefers will add. Hope this helps