What is the difference between Central and South American Cichlids if any? We know location is a given...

[Cichlidfever]

Is it beauty?
Is it aggression?
Is it size?
Is it what they eat, how they eat?
Is it living in fast or slow water movement?
Is it just the landscape/aquascape?
Is it how they are built?

Can we look at the two and pick out what is the difference?

 

[Sinister-Kisses]

...it is literally potentially ALL of those things depending on each individual SPECIES. Not simply South vs. Central.

 

[duanes]

Let's start with water. Most water in Central America is hard, high pH and mineral rich.
In Amazonia water is generally much softer, lower in pH, and mineral poor, because the Amazon rainforest sucks up all the mineral,s and nutrients almost immediately. A pH of 7.1 (common in S America), is 100 times more acidic, than an 8.1 common Central America. (each 10th lower or higher on the pH scale, represents 10 times)
So how does this affect the fish? you may ask.
Cichlids in S America have evolved to resist bacteria, common in soft low pH water, not the kind of bacteria Central Americans have evolved to resist over millennia.
One thing that is common, is that both the water in Central and South America, has non detectable nitrate concentrations, so give either continental cichlids elevated nitrate, along with an out of range pH, and stress is the result, and often leads to chronic disease.
I collect cichlids in Central America, and test for pH and nitrate in whatever river I collect.

Although pH in Panama may range from 8.2 (left) in some rivers, it may drop to 7.8 in others, as you can see the left tube in both shots, nitrate remains undetectable.
Flow may change, but the cichlids that inhabit a river may be species specific.

In the fast flowing river above, I catch totally different species than in the river below, even though they are not that far apart

As far as aggression goes, in Amazonia, cichlids come from communities of many various species, so aggression is often tempered.
in much of Central America there are only 1 or 2 species that inhabit a large stretch of geography, which seems to intensify aggression.
But.... in South America, in the rivers west of the Andes, there may be only 1 or 2 species present that inhabit a certain system, so aggression in those river systems is also heightened, and similar to Central Americans. Where Mesoheros festae is found it may be the only cichlid species present, or where Andinoacara rivulatis is found, and it may be almost the only cichlid present , and their common monikers reflect that aggressive status,( Red Terror, and Green Terror), this may be why combining the 2 west Andean species, above, with Amazonian types they would never come across in nature. can be problematic.
Another similarity is, the rivers on the west of the Andes are chemically more similar to those of Central America, than they are to Amazonia.

 

[Hybridfish7]

I wanted to say you can't really generalize them, because there's species of each niche across both areas, and how south america has too much variety to generalize, but that just made me convince myself that there are differences halfway through writing this.

I'll start off by saying all central american cichlids belong to the tribe therapsini, and while there are some genera belonging to therapsini in south america (kronoheros, caquetaia, australoheros, uaru, heros, pterophyllum, mesonauta, symphysodon, hoplarchus, hypselacara, etc) there is, as mentioned before, a lot more variety in south american cichlids, as they have had a lot more time to diversify than central americans. There is generally a lot more variety in shape, as much as I hate to admit, as in central americans they generally follow the trend of "rectangular body stretched or compressed laterally or vertically, with a face that is also either stretched or compressed to some degree with different mouth placements". In south americans you have more extreme changes, like those you can see in pikes vs peacock bass vs angels vs discus vs apistos. South americans tend to prefer softer water of lower pH, but there are some that prefer higher, like those in the northwest of south america in the Andes. Central americans generally prefer higher pH/harder water.

There are species from both areas that prefer different temps, like central american thorichthys from the helleri group and south american gymnogeos preferring cooler water. And then there's things like angels, discus, and apistos that prefer warmer water, same with central american species like sajica, at least in my experience. My sajica would get cold shock if I tried to do cold waterchanges. I actually don't know of any rheophilic south americans, at least not ones specialized in it to the degree of certain centrals, like tomocichla, chortiheros, or rheoheros.

 

[duanes]

And speaking of temps, those on either extreme ends of geography are very different than those from equatorial areas.
Cichlids found in northern Mexico come from more sub tropical temps. (Mayaheros beanii, and the Herichthys carpintus clade)
Just as cichlids from far south in South America such as Uruguay and Argentina often require winter cool downs, and should not be mixed with equatorial species. (Gymnogeophagus, and Australoheros)
The photo of the winter scene below, was taken near Buenos Aires, Argentina

 

[Mazan]

in much of Central America there are only 1 or 2 species that inhabit a large stretch of geography

I have been thinking about this, and the aggression levels related to number of coexisting species is an interesting hypothesis. But I am not sure how generally the only one or two species rule applies for Central America? The streams I worked in in Panama had 3 species of cichlid (Gatun lake had Just one, but non-native and it had eliminated the smaller species that previously occurred there). And in Belize, while the higher mountain streams had just two cichlid species (Cryptoheros spilurus and Trichomis salvini), in the lowland rivers and lagoons at least 7 cichlid species coexisted (The previous two mentioned plus Vieja melanura, Petenia splendida, Mayaheros uropthalmus, Rocio octofasciata and Parachromis friedrichstahlii). I was there a long time ago and I know that now Tilapia have been introduced in much of Belize, so perhaps there may not be as many native cichlids coexisting there these days? I have been told that the native cichlids are no longer as abundant as they were then. Or perhaps Belize is the exception to the one or two cichlids only rule in Central America?

 

[Hybridfish7]

I have been thinking about this, and the aggression levels related to number of coexisting species is an interesting hypothesis. But I am not sure how generally the only one or two species rule applies for Central America? The streams I worked in in Panama had 3 species of cichlid (Gatun lake had Just one, but non-native and it had eliminated the smaller species that previously occurred there). And in Belize, while the higher mountain streams had just two cichlid species (Cryptoheros spilurus and Trichomis salvini), in the lowland rivers and lagoons at least 7 cichlid species coexisted (The previous two mentioned plus Vieja melanura, Petenia splendida, Mayaheros uropthalmus, Rocio octofasciata and Parachromis friedrichstahlii). I was there a long time ago and I know that now Tilapia have been introduced in much of Belize, so perhaps there may not be as many native cichlids coexisting there these days? I have been told that the native cichlids are no longer as abundant as they were then. Or perhaps Belize is the exception to the one or two cichlids only rule in Central America?

I'd say it's about a 60/40 split with most areas being low in cichlid biodiversity, like in south/western Mexico or from Guatemala to Nicaragua with the exception of the great lakes. There are a few exceptional areas scattered around there, like southern/central Belize as you mentioned, the great lakes of Nicaragua as previously mentioned, northern Honduras, and the Chiapas/Tabasco areas of Mexico. Costa Rica is probably the most biodiverse when it comes to cichlids aside from Belize. You'll find things like parachromis, amphilophus, cribroheros, hypsophrys, and sometimes multiple amatitlania species in the same part of the river. Not to mention neetroplus and tomocichla in faster parts of the rivers. I can't really speak for panama but I know a lot of species have overlapping ranges.

 

[duanes]

Yes it may seem to be hard to generalize, but even within a small stretch of river, there are microhabitats, that tend to separate out certain cichlids from each other, as it does and other species like Gobies.
In the rheophillic habitat of Rio Mamoni , Darienheros and Isthmoheros cichlids were normally netted, but not the Andinoacara,
Yet in more static slow flow zones, only a mile os so north of the rapids, the Andinoacara were common, but not the Darienheros.

The above sketch of slow moving river is where we found lots of Andinoacara, but no Darienheros.
Below is the type flow where Darienheros dominated.

The only fishes that seemed to transcend water flow preferences of these miicrohabiats were the tetras, netted in either fast or slow flow rate, at any time of day.

Hard to see from above, they are well camouflaged on the stony substrate, but they are there.

 

[Mazan]

Yes, but that is also true for many South American cichlids.

I totally agree .
If I was able to keep S Americans,
I wouldn't keep slack water preferring severums, or oscars, with rheophillic Geophagus, or Retroculus in the same tank.

one size (flow type) does not fit all.
And I realize most aquarists tanks do not provide current close to the rheophillic walls of flow in nature, but I at least try in tanks with rheophillic species.
By Using a recycle rate of 1500gph flow, (sump to tank) and an added 500gph wave maker across the 6ft length of the tank..

 

[neutrino]

Agree that it's hard to generalize, as it seems to me, considering the diversity within both regions-- except I don't know of any with body shapes quite like discus, angelfish, Heros, or Mesonauta in Central America (though there are fish believed to be related to them).

I'm not sure where the term "therapsini" comes from? The term I am familiar with, "therapsids," refers to a group that predates the dinosaurs, with mammals being their only remaining 'relatives.'

What I do know is, while details of dating, colonization, rate of adaptation, genetic relationships, etc. have been debated, the scientific consensus seems to be that Central American cichlids originated from South America-- and (as I understand it) are generally considered to be of Heroine lineage, with, for example, those resembling Geophagines believed to have filled those morphological, environmental, and trophic niches due to no geophagines already filling those niches.

There's a huge volume of literature on all of this...

Phylogeny and biogeography of 91 species of heroine cichlids (Teleostei: Cichlidae) based on sequences of the cytochrome b gene - ScienceDirect

Within the remaining heroines, Hyspelecara and Hoplarchus are recovered with low support in a basal position with respect to a clade that includes Heros, Uaru, Mesonauta, and Symphysodon, and the circumamazonian (CAM) heroines. The first clade is restricted to South America. The largest clade of heroines, the CAM heroines, include more than 85% of the species within the tribe. This clade is mostly Mesoamerican, but also contains four species found in the Greater Antilles (Nandopsis), and three genera found in South America (the ‘Heros’ festae group, Australoheros, and Caquetaia). Up to eight major lineages can be recovered within the CAM heroines, but the phylogenetic relationships among them remain unresolved. Two large suprageneric groups can be distinguished, the amphilophines and the herichthyines. The amphilophines include Amphilophus, Archocentrus, Hypsophrys, Neetroplus, Parachromis, Petenia, and five additional unnamed genera (the ‘Heros’ istlanus group, the ‘Amphilophus’ calobrensis group, the ‘Heros’ urophthalmus group, the ‘Heros’ wesseli group, and the ‘Heros’ sieboldii group). The herichthyines include the crown-group herichthyines (Herichthys, Theraps, Vieja, and Paratheraps) and the genera Tomocichla, Herotilapia, and Thorichthys, together with three unnamed genera (the ‘Heros’ umbriferus group, the ‘Heros’ grammodes group, and the ‘Heros’ salvini group).