B. rainbows!

How did you acclimate them? Seldom are rainbows kept in BW in LFS. Could be stress from the sudden change. Rainbows will thrive in FW, as well, and are usually sold as such.

How high is your SG? I think these would only be ok in low-end BW. Nothing over 1.005.

Don't most rainbowfish come from more acidic water? I thought the celebes rainbowfish was the only true brackish rainbowfish?

B. rainbows colours

All you ahve to do is buy colour enhancing foods. The brand that i use with my ruby scat is Omega One Formula One MArine Pellet. These are sinking pellets, however they sell a flake food that has this super colour enhancing formula. Just get the packages that say SUPER COLOR ENHANCING or something to that effect, but ill tell you what my ruby scat is brighter red than i have seen in any pictures online or in books. She is almost neon red on her head and all throughout her body from these pellets. The only thing that these pellets have in them is a carotene additive that is completley natural and taken from carrot extract to enhance red colors . So hope that helps you.. there are other brands and they all have color enhancers, just make sure it says it on the package.

There a few rainbow fish found in BW.
Boeseman's rainbowfish are rarely in BW.
Inhabits lakes which are situated at the headwaters of the Ajamaru River in Irian Jaya which drains into the Kais River eventually flowing to the Ceram Sea

BW Rainbows:
Melanotaenia nigrans Black-banded rainbowfish
Telmatherina celebensis Celebes rainbow
Marosatherina ladigesi Celebes rainbowfish

I have also seen N.G. Red Rainbowfish in BW.
I don't know if the will survive in BW. I have not seen anywhere stating that they are brackish.