New Isopod Keeper. General Tips/Guides Welcome

[FascinatingFamiliars]

Hello! I'm just getting into the hobby, I went to a reptile show in my area looking for Emerald Tree Skinks and found these wonderful little guys instead. I'm interested in breeding them since they make great sources of protein and I also think they're funny 'lil guys.

I've got the basics down. Moisture, protein, leaf litter, substrate, etc. Any specific tips or tricks people would have along with recommendations would make me very happy, and I'd also just love to find some other folks in the community. 

Here's my currently stock:

• 1 culture of 10-ish Dairy Cows (Porcellio laevis)
• 1 culture of 10-ish Zebras (Armadillidium maculatum)
• 3 cultures (1 failing, more on that if asked) of Springtails

Right now I'm keeping everyone in pretty small deli cups. The plan this weekend is to expand them to larger dedicated bins, lots of substrate. My goal is to make a substrate composed of charcoal, cocoa chips, cocoa fiber, orchid bark, sand, spagna moss, and topsoil with varying ventilation. 

Here are some general questions I have right now:

• The fish food pellets/yeast I'm feeding them keep producing mold, even from a single day of being left in the tank. My general understanding is that this is bad because of pests like mites, so how do I stop this from happening?
• Are there any better food sources I should know about?
• Did I pay a fair rate? The Zebras were $25 and the Dairies were $20, and the dairies don't have a super bold patterning.
• What are starting tips to get into it from a business side? How do I get into reptile expos and such, and what's a good suggested starting stock to bring to something like that?

Thanks in advance for all the advice!

[Allpet Roaches]

Welcome! I'd suggest bigger containers for the isopods. Try vegetarian foods. You can get them far cheaper online but there is shipping cost and possible DOA. The zebra and dairy cows are probably among the best staples for trading.