S. American Cichlid Community Tank Ideas


Feeder Fish
Jan 30, 2019
Hello Fellow Fish Lovers,

A little background to explain my situation. For the last year I have been testing a "no water change" 220 liter aquarium for a company. The goal of this test is to determine if their filteration system works as they advertise - basically, beautiful tank with little to no work. The tank is currently stocked with Lake Tanganyika cichlids (Neolamprologus marunguensis (reproducing like crazy - can't count), Julidochromis trancriptus (2 because I am trying to move them out), and 3 catfish). The water has remained stable for the past 10 months, with nitrates remaining at 50 mg/L (acceptable, but a little high in my opinion). All other parameters are spot on.

This month I will be receving a new tank from the same company to be tested. This time a much larger tank (1,130 liters tank (200 x 70 x 80 cm)). I am a fisher lover and have been since I was 4 years old. However, I am completely overwhelmed to pick the setup for this tank. This has never happened, I normally am buying tanks to make my ideas come true. And truthfully, I really want freshwater stingrays, but they would not be good testing fish since, I can't change the water and they produce a large amount of ammonia.

I know that I would like a root/plant tank setup (yes, I know my next sentence is going to contradict this idea a little, but I have faith I can still have plants (just attached!)). I been thinking of setting the tank up with some geophagus because I love watching fish sift through sand. I have been researching these guys quite a bit, but still haven't found the information I am looking for:

1) what are the best tank mates for geophagus?

I know they can be house with the normal S. American species - tetras, angelfish, hatchetfish, corys, etc.

2) I am looking for an active, fun tank. So, naturally I would also place some corys in there. Angelfish in my mind are pretty docile, would they help calm the tank so that it looks more balance when watching the fish (not that you get dizzy from all the action). Or, would some tetras or hatchetfish look better? Some color to jazz up middle/top water.

3) I know the geos are passive, but will they hog the bottom of the tank? Meaning, should I focus on more middle level fish as tank mates? I am interested in the larger geophagus species (altifrons, for example), how much space do they require to remain calm and not become aggressive?

4) Can I mix some geos with other geos? Or with some dwarf cichlids?

5) And if you are really bored: if this was your tank how would you form the community?

I have always had Africa cichlids or Asian fish, so moving into a South American tank setup is all new for me. Normally, I would visit petstores and watch the behavior of all the fish, but at the moment this is not a possiblity for me. So, not knowing these fish and their behavior I am a bit more worried than I normally would be.

Thanks in advance for all your helpful comments!


Blue Tier VIP
MFK Member
Nov 28, 2011
San Diego
So did you ever measure the TDS (total dissolved solid) value of this no water change tank? TDS values does affect the fish's osmoregulatory process in the long term. They can get used to increasing values over time, but the same increasing values can cause stress and affect growth.

I really don't recommend no change water for soft water, low TDS value SA fish.


Feeder Fish
MFK Member
Mar 22, 2017
Houston, Texas
1) tetras and ancistrus. Hatchetfish if you have a lid. Corys are redundant with the gems as they are both bottom dwellers. If you're looking for more cichlids and want to keep plants, I would totally recommend festivums. One of th greatest, most underrated of the SA cichlids. They are extremely intelligent and curious and are constantly exploring the aquarium. They also stay near the top to contrast the geos.

2) It's a matter of preference, but I would take festivums over angels all day, every day. For some color, you can get some lemon tetras, some bleeding hearts, and an albino ancistrus.

3) It's as such a question of layout as it is size. There will always be squables over territory if the fish cannot identify a space for itself. With the size you have you should be fine if you break up the lines of sight. Even when geos squabble, it is not so bad.

4) Yes. I have Sveni with Mirabilis and a RHT. Less squabbling between the species. You can do dwarfs too if you like, but that's up to you.

As this is an experimental tank, I would opt for some of the hardier fish than for something exotic. Mirabilis are sensitive for geos, but RHT are solid like a rock. The seven's seem to be as well. I've had mixed experiences with the Neambis. I personally would pair them with the festivums and get a nice school of lemon tetras and a couple of Ancistrus and sit back and enjoy.
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