Originally Posted by gondo
Yes this dwarf cichlid looks interesting. It is a bit larger than the Neons yet peaceful, and colorful. Also called butterfly cichlid cause of all the colors. They also require the low PH soft water free of any contaminants just like the RO water I have. This is one fish I will consider. Thanks.
The common ram, Mikrogeophagus ramirezi, is not an easy fish. It is particular about water parameters, and in your case the temperature would be an issue. This fish never does well below 80F or higher. Neons won't last long above 80F as they are better suited to what you have now, 75-77F. I would not mix these. The corydoras also are healthier at the lower temperatures; some species, like C. sterbai, can tolerate higher temperatures which is why they are often recomended for discus and ram aquaria, but most of the common species fare better in cooler (mid-70'sF) water.
But the Bolivian Ram, Mikrogeophagus altispinosa, is different and would suit your setup. It does well in lower temperatures with the neons and corys. Quite a peaceful cichlid, and it does well as a lone fish, just one in the tank. In a 29g, one or a mated pair (male/female) would work, but this is not an easy fish to sex especially when young and small as they usually are in stores. Two males would be constantly threatening and harassing each other unless they have space to establish and defend their individual territories. But one of these with neons and corys (and yes, a few more corys is recommended) would be a nice display.