I have collected this fish in both small creeks and the Rio Negro one of the widest rivers in the world. This fish is relatively, “normal” when young but as it grows it develops a truly beautiful lyre tail as it grows.
The most recent pair I have, came from Belem, with what appeared to be A. cf. pertensis, and Nannacara taenia
Size: This apisto can grow over 2 ½”
Distribution: I have caught this apisto up in Boa Vista and in the Rio Negro a few days boat ride up the river from Manaus.
Aggression, tankmates: These fish are peaceful and will easily be bullied. They have long flowing fins that will be shredded by tankmates.
Housing requirements: I believe that a ten gallon tank is to small for life for this fish 15 gallon minimum. These are harem breeders and it is ideal to keep one male with three females. As with most apistos, A ph from 5.0 to 6.5 is preferred, tank raised specimens will tolerate higher ph levels. This fish is susceptible to fin rot especially when kept with boisterous tankmates.
Notes: If I understand correctly there are to variants of this species, on comes from southern Brazil and one from the northern part. I have had a few A. gibbiceps that occupy the middle to top zones of the aquarium while others frequented the bottom zones.