Thanks for all the advice. I will most likely go with Rams to try something new. How should I go about finding a bonded pair? Will I be able to tell just by observing at the LFS? I took a look at buying online via Aquabid, perhaps that is a better move to guarantee a bonded and breeding pair. Also, if I go through the LFS, would it be better to buy a group rather than a pair?
What I will write applies to either ram species,
Mikrogeophagus ramirezi (the common or blue ram and the several varieties developed by selective breeding such as the German Blue) and
Mikrogeophagus altispinosus (the Bolivian Ram).
Like most if not all cichlids, to varying degrees, rams must select their own mates. I have put together male/female and had a few spawnings before the male turned and killed the female. Nothing is guaranteed, but bonded pairs tend to be more successful.
Colouration and finnage are not always reliable indicators of gender, particularly in immature fish as one generally sees in stores. If there is a group in the store tank, remain very quiet in front of the tank for a while (10-15 minutes or longer). You will easily spot males, as they will be "charging" at one another, not usually actually engaging in physical contact, but sort of poking towards each other. Once you see a nice male, look for females close to him; these will usually be completely ignored by the male, and the female closest is probably one with which he will bond. The longer you observe, the more reliable this can be.
Acquiring a group yourself and letting this take place in your home aquarium will work, and in a correctly-aquascaped tank of sufficient size you might even get a pair forming and spawning, which would be an obvious sign of bonding. The problem with this is that you then have to remove the others, unless the tank is really large enough for all of them, but unless you have a tank of 6+ feet this won't likely work long-term. Rams are not inexpensive either.
I wopuldn't necessarily trust anyone online; as I've discovered myself, a male/female "pair" may spawn but not be bonded. Of course, bonding can break down, there is no guarantee, but it is a safer bet.
Remember the common ram needs warmth, at minimum 80F/27C. Cardinal tetra are good dither fish. They remain in the lower half of the water level, like the rams, so for upper level fish you can look at pencilfish and hatchetfish. Not every species will work, but there are a few.
Corydoras generally prefer cooler water, but there are a few species. Essjay mentioned C. sterbai which is one of these, and often available as this species is now being commercially raised. However, cories are a problem if you want fry from the rams. Cories are semi-nocturnal, by which I mean they are active during daylight but also very much during total darkness; rams are not--I have more than once had eggs disappear to catfish overnight. Once, during the day, I observed a trio of cories come upon a shoal of blue ram fry being shepherded by the female, and within seconds the fry were gone into the cories. The ram had no possible chance of staving off three cories, with their "armour" plating. So if you want fry, leave out any catfish, or any nocturnal upper fish.
Sand is the best substrate, as cichlids are substrate feeders. Like cories, they will pick up a mouthful of sand, sift it around looking for food tidbits, then expel the sand. Sometimes this happens through the gills, which is very common in cories. So a smooth sand like play sand is ideal.
Byron.
