Best way to stock on a budget is to find a
local aquarium club and get frags. They maybe small at first but will grow quickly on a well maintained and fed system
.
Mandarins can be tricky, even ORA captive bred ones, IME. If you are getting them from a store, make sure that they are actually keeping the regimen of feeding prepared diets and look for full bellies..."TIP"...look from the underside.
Get as large as you can. In a system as small as yours, they will decimate the "pod" population. Although the ORA are fed w/commercially prepared foods (chopped PE Mysis, frozen
Cylcopeze,
New Life Spectrum Grow 0.5mm pellets,
Golden Pearls 800-1000micron) it's best that you get a little breeding trap and reinforce training to commercial foods and hand feeding w/a pipette/eyedropper.
To get it feeding on the dry foods, soak it with thawing frozen food so the liquid portion (and scent) in absorbed by the flake/pellet. Then over time once it's accepting the soaked food, add unsoaked food and reduce the amount of soaked. Once you notice that it feeds w/o issues, then release into the main display.
Yeah, it's a bit of work but well worth it to keep these little jems. I haven seen this color variant in 10 years, but there were orange/peach faced mandarins.