Mixing Geophagus

[stiker]

Hello,
I am looking to free up some room in my 75g tank for some new species I have coming to grow out.
I am planning to move the 5 Geophagus Steindachneri (ranging from around 1.5inches to 2.25inches - 1 male and I am pretty sure the other 4 are females) into my 180 gallon tank that currently houses:
10 Geophagus Tapajos (Ranging from around 2.5inches to 3.25inches)
30 Lemon Tetras
6 Brochis Cories (Brochis)
4 Pseudohemiodon Lamina

I am aware that as the Geophagus Tapajos and other fish grow I will need to reduce numbers. My main concern is how well will the two different species of Geophagus get along especially due to the size difference? Will the two different species still have their own Hierarchy and will the dominant males/females of each species still show their colours? I am not too concerned about them inter breeding as I know they both imply difference breeding techniques, but more so them co existing together. From what I have seen people are able to mix different species and from what I have read the Steindachneri are slightly more aggressive which may be a benefit of them going in after the Tapajos?
The tank has a fine sand substrate along with large pieces of driftwood and plants to break lines of sight.

 

[duanes]

Although they may get along fine if you are lucky, in my experience (and I have kept both species you mention) is I have found that the more highly alkaline water Geophagus from west of the Andes (steindachneri, pellegrini and crassilabrus) are on an entirely different aggression level that those soft water species from east of the Andes (with the exception of the braziliensus group) and will often kick the living snot out of the mild mannered (by comparison) easterners.
I believe the Tapajos are way to wimpy to be housed with the likes of steindachneri.
Consider the cichlid species living with steindachneri in nature, Mesoheros festae, Andinoacara, and Mesoheros gephyrum. To coexist these Geophagines have had to develop attitudes that have more in common with Central Americans than their mild mannered cousins in the Amazon basin.

 

[Serpentine]

Wow, an eartheater that can hold its own against festae is pretty hardcore. I sure wouldn't want that in with my peaceful RHT or abalios.