@Byron;278782 Wow, congratulations!!!!
I actually considered Pencialfish for one of the larger tanks too (45+55g) but I am unclear as to their behavior vs Tetra behavior so I didn't follow this idea any further atm. What is your thoughts on this? Who is with them in your tank?
@Calmwaters Thank you :-D
Generally speaking, pencilfish are fine with tetras (and hatchetfish). All these are characins. The family Lebiasinidae holds two sub-families, Lebiasininae and Pyrrhulininae; the distinction is the patch of teeth on the palates of the former making them a predatory tetra-like fish. The latter sub-family contains some lovely aquarium fish in its two tribes; Pyrrhulinini have upturned mouths and lack the lateral line, and include the Splash Tetras and similar small fish. The other tribe, Nannostomini, contain the pencilfish. More sensitive to water parameters and quality that the common tetras, so one has to pay attention to that. They all occur in very quiet calm waters thick with plants. There are two genera recognized now, after Gery (1977), Nannostomus [from the Greek for small mouth] and Nannobrycon [from Greek for small biter]. The names are a clue to feeding; these fish need fine foods and can be fussy, although some are as adept as tetras at eating anything offered.
The genus Nannobrycon contains but two species, N. eques (common name diptail pencilfish) and N. unifasciatus [meaning single line or stripe, a reference to the one blackish lateral line on a buff-coloured background]. I have both in my 90g, and it is the former that has spawned probably several times in the past few months. Gery set out the internal biological differences between the fish species in this genus and those in Nannostomus, but the easy way to tell tham apart is that the two Nannobrycon species always swim at an oblique angle, head up about 45 degrees. All species in Nannostomus swim horizontal.
I also have a pair of Nannostomus mortenthaleri in the same tank. A recent species discovered in 2000 and named after the exporter who discovered them in the Rio Nanay (their only known habitat); I had a small group imported direct from Peru, but they refused to eat or stopped eating one by one right from the start, until only the pair were left and they have been in there for several months now. Interestingly, FishinPole mentioned he had a similar experience with his group. I have Hyphessobrycon metae, Paracheirodon simulans (the false or green neon), hatchets (Carnegiella marthae and C. myersi), Poecilocharax weitzmanni, Farlowella acus--all of these are wild caught; and Corydoras pygmaeus, C. panda, C. similis and Aspidoras in this tank.
I have a group of Nannostomus beckfordi in the 115g; this species is the most robust, the males can be a little rough at times, driving other fish away from their "space" but not in my experience leading to any injury. Still, they need room to keep the stress down for the co-inhabitants. These fish regularly spawn. Haven't had fry lately, but I did back in the late 1990's. This species does very well with dwarf cichlids; the males are not easily bullied.
All pencilfish males drive the females hard; I try to get a ratio of 2 males to 3 females or multiples of this; I started with 8 beckfordi, 4/4 because that's all they had, and lost 3 females within 4 months through the males behaviour; I've added more females as I have found them. This trait is noticeable even with the Nannobrycon eques.
For the most part, pencils behave like tetras, only more sensitive and demanding at times.
B.