If you're trying to make a community tank I would loose the firemouths. I know a few places and books say that you can keep them in community settings but the truth is you can't without paying special attention to how the aquarium is organized. A cichlid is a cichlid is a cichlid in the case of both blood parrots and firemouths the difference is just their size and physical prowice (sp?). If you wanted to keep firemouths you would need a large aquarium that would be able to give them enough space that the cichlids wouldnt come into contact with the nesecarialy large groups of smaller fish. If you have kept cichlids in the past this is easy to do but I would not suggest keeping aggressive cichlids in a community setting unless you are well versed in cichlid behaviour and thought processes. With something like firemouths, you might not end up with a tank of dead fish if you set up the environment incorrectly, but you would certianly have a tank of stressed out and damaged fish along with some smug fm's.
However, people generally do have luck keeping blood parrots in community and planted type settings. This is because of the nature of their deformed mouths however. A blood parrot may want to kill a fish, but if it cannot fully close its mouth, it can only badger it, never seriously injure it. However, a blood parrot does have the mind of a big cichlid and the personality to boot, so if it feels like it has a chance, a bp or group of bp wont' hesitate to bother smaller fish to death. I have also seen and heard of larger blood parrots sucking up small minnows if they can get their beak around them : O
If you are going to try this, you may have more luck, but once again I would suggest a bigger tank. Also the ratio of smaller fish to blood parrots must be such that the blood parrot in all his pompous thinking won't assess the situation and come to the conclusion that he and his cohorts can chase all the other fish to exhaustion or until they jump out of the aquarium... as any sociable cichlid seems to want to have the tank to himself and his own kind.
As for your experience in oscars, I find them to be relativeley docile cichlids, as they are open water. ca cichlids with a flat bottom (indicating they feed off the ground) tend to be more territorial, as they need to protect their space of ground from fish that may try to take their food. I would reccomend keeping firemouths and blood parrots out of a community setting first before trying to incorporate th em into a peaceful environment, as they tend to be relativeley domineering.
I and others i have known have had the most experience with cyprinds in community settings rather than characins, and not with livebearers. In a community setting with cichlids they will be the primary bottom feeders, and will treat any fish that enters their space as an affront to their land holdings. (except for things like plecos, I have had no problems with these, but as they are armoured and look like a piece of wood to a fish this could be for any number of reasons.)
So what you're left with in this situation is to stock the middle and upper strata of the tank with fish that are either too fast or too large to be viewed as either food or equals. Cichlids tend to attack things that look like them that is a similar size, which indicated that they share the same trophic level and thus the same food sources.
Livebearers in my opinion are out. They are relativeley slow and full bodied which makes them a target. Though I have kept convict fry in a 29 with young variatus.. I did not have any babies that year. the convict fry also started to kill the variatus when they grew to a comprable size. Remember a cichlid just wants to dominate their environment so you can't make it too easy for them. Swordtails do live in the same environment in the wild, but they occupy different niches. For example, shiners and bass live together in the same stream, but you wouldnt keep them in an aquarium. Firemouths are not predators of swordtails, but they would seldom come into contact in the wild. FMs occupy the bottom of deeper parts of a stream while swordtails occupy the shallower parts where they feed on insects at the surface.
As for good potential candidates.. I would reccomend barbs. My personal favourite is the spanner barb or "T" barb Puntius lateristriga. As they grow at relativeley the same pace as smaller cichlids and attain relativeley the same size in aqiaria. OF course they can grow to up to a foot (i know the web dosent say this but ive seen it) but they often don't in home aquariums. Another plus about this fish is that as they grow they tend to break out of schools and live a solitary lifestyle.. which is great if you need to thin out your flock as they get older for space requirements.
If youre into smaller barbs.. I know many people have had luck with things like tiger barbs and other species of the more agressive, more tightly schooling varieties of barb that are available. They defend themselves as a unit and are very fast moving, which makes them difficult for cichlids to attack.
I have had great luck as well with giant danios. I feed these to my large knifefish so sometimes I will get a school and put them in one of my cichlid tanks as dithers then just use them at my lesiure. The great thing about giant danios is that they are VERY fast.. and they do the '1 up 1 down' defense strategy that makes danios so sucessful against predators. The downside to giant danios is that when frightend they jump, and they are excellent jumpers. You can keep a tight hood on your tank but still there is the possiblity of self injury from hitting the hood.
As for non schooling fish, decent sized gouramis seem to work well with cichlids. My mom has a 55 gallon that she keeps convict cichlids and blue gouramis in. I was sceptical when she tried it but it has worked out well for her for months now with no problems. Upon learning of this I asked around and found that many people do this to great sucess. The good about the gourami is that it is large and sticks to the top, which makes it not much of a threat to bottom-dwelling cichlids. my primary concern was that their "feelers" (or whatever you call them) would get pulled off, but everyone I have talked to has said that this has not been a problem.
The species most people have had sucess with is Trichogaster trichopterus, the three spot gourami, blue gourami, gold gourami, cosby gourami, platinum gourami, etc... as far as I know they are still all the same species. I would not reccomend kissing gouramis or dwarf gouramis however, as dwarf gouramis are too small and kissing gouramis behave and look too much like cichlids.. they tend to get into fights with cichlids ime.
As for other things I would try but havent... there are rainbow fish. Hopefully someone will chime in as ive often thought that this would work, but as of right now I'm not a fan or rainbows, so I've never kept them.
If you want a tetra, something like astyanax mexicanus (buenos aries) could work. they coexist with ca cichlids in the wild and are boisterous and fast enough to outrun them. I would not try characins from further south though as they tend to get more delicate and diminuitive as far as the commonly kept aquarium species go.
SO there you go. sorry if that seemed rambling but I have a lot of opinions on the topic and am just amassing more.
If you have a large tank you can try it out but be warned.. and have a place to move the fish to. If you are just starting out you can try this, but keep it simple. My first foray into south american cichlids was an attempt at this (albeit unknowingly, I was 12 years old).. I was given a 46 gallon bowfront tank for christmas and stocked it with all different kinds of things that didnt work, as my knowledge was lacking but my spirit was huge for the endeavour, as is common among children. What eventually ended up staying stable for me for several years was a school of spanner barbs and two young convict cichlids. Of course they turned out to be male and then fought to the death for control of the tank, but they never had trouble with the barbs.
So I suggest you go for it with caution. But if you really want to get into cichlids and learn about their intricate and always amazing inner life, I would suggest you pick one cichlid and try a species tank. There is much to be said about a community of individuals over a community of species. There will be a learning curve with a trail of dead bodies if you go headlong into combining cichlids with community fish.. but done with caution.. it can be attained. But i'm still all for cichlids. theyre great people : )
