Rainbows, Congos and Shrimp?

The congos will get too big for your 12 gallon long. The forktails will snack on your shrimp.

Yipes! Any recommendations?

I myself keep the psuedomugil gertrudaes in with neos and they seem to keep the colony in check. I will certainly agree that the only shrimp safe fish I have seen is the oto, so any fish are assumed predators of shrimplets for certain. If the shrimp breeding colony is not the focus of the tank, then the adults have seemed to do well with the blue eyes. With solid feedings and dense foliage your chances of breeding and successful shrimplets increases drastically. The Kubotai microrsbora is another idea that has similar colors to the congo tetra, but nothing nearly as impressive. What are your desires for the tank, colors, size, stratums occupied. These will help in recommending species that might work or have worked with my neos in my personal aquariums.

Yea they will snack on your shrimp so that is not suggested...I havent had much luck with any fish in shrimp tanks. They can survive and breed but you will not have much success. They will generally leave the adults alone but little shrimps will get eaten as a snack.

The tank is planted, but things are just starting to fill in so I have a lot of floating plants (Ricca, subwassertang, spangles) to boost the biomass. The substrate is Eco Complete with white sand and the rocks are black lava rocks (I'm trying to go for a beach look - think Galapagos) and the plants will hopefully fill out the back half of the tank. I have a lot of medium-height hair grass in the very back.

I'd like to have a small school of colorful (cool end of the spectrum) unusual fish that wouldn't gobble up my shrimp. In fact, it would be very cool to have the shrimp and the fish reproduce, which would of course, necessitate another tank…but you know how that goes.