Photo thanks to discusnoob

Name:
Scientific name: Nannostomus rubrocaudalatus
Common name: Purple Pencilfish
AKA: Nannostomus sp. ‘purple’/ N. cf. marginatus ‘red pencil II’/ N. sp. ‘coral red II’.

Country of origin: South America - Peru

pH: 4.0 - 7.0
Temperature: 24 - 28c
Hardness: 18 - 90 ppm
Water flow: low - standard
Oxygenation: standard

Maximum size: 3.0cm


Diet: Live, frozen, flake & pellet food of suitable (smal) size - it is a micropredator. It should be given live or frozen food daily.

Breeding: Males - more colourful & streamlined than females. Larger anal fins.

They are an egg scatterer, and if provided with a mop or sufficient moss or plants, they can lay eggs, however they need to be kept from them by a division in the tank, or removal of the eggs or fish. They will also not provide any care, so removal of the parents is still the best plan.
Pairs are territorial when spawning.

Tank companions: They hunt red cherry shrimps as adults.They would try for crystal red adult shrimps, but may not be able to kill them unless working together. They would certianly take shrimplets until near adult size. They are OK with Caradina typus, which are much larger.

They are the most voracious hunters of shrimp I have kept in the tank - even compared to Gold Line Pencilfish. Odd, since the write-ups I have seen have all said that pencilfish are ideal for keeping with shrimp.

Other microfish are suitable tankmates. I have kept them with bororas; danios; chocolate, liquorice & sparkling gouramis; green neon & ember tetras; male endlers and royal whiptails. They live in their natural habitat with apistogramma species. Despite their continual non-stop hunting of shrimplets, I have never observed them to display any aggression toward or interest in other fish as prey.

They prefer a dark substrate, heavily planted, with blackwater from decaying leaves (Indian Almond Leaves are ideal) and floating plants.

They require a mature tank - do not add them immediately after setting up a new tank, and the tank should be 3ft or larger.

They do not school well. Males are terrirorial and capable of inflicting injury on each other if the tank is too small. A group of 10+ should be kept to spread aggression.

Their colour will probably fade when the lights are off, and return gradually as the lights come on.

They will intimidate smaller tankmates, such as the bororas, who will become very shy in their presence. The others are fine.


Confused with:
There are 19 species in the genus:

Nannostomus anduzei
Nannostomus beckfordi - Gold line/ Beckford's/ Golden/Brown pencilfish
Nannostomus bifasciatus - Two-lined/whiteside pencilfish
Nannostomus britskii - Spotstripe pencilfish
Nannostomus digrammus - Twostripe pencilfish
Nannostomus eques - Honeystick/Brown/Rocket/Brown-tailed/Diptail/Tubemouth pencilfish
Nannostomus espei - Espe's/Barred pencilfish
Nannostomus grandis
Nannostomus harrisoni - Harrison's/blackstripe pencilfish
Nannostomus limatus - Elegant pencilfish
Nannostomus marginatus - Dwarf pencilfish
Nannostomus marilynae - Marilyn's/greenstripe pencilfish
Nannostomus minimus - Least pencilfish
Nannostomus mortenthaleri - Coral-red pencilfish
Nannostomus nigrotaeniatus
Nannostomus nitidus - Shining pencilfish
Nannostomus rubrocaudatus - Purple pencilfish
Nannostomus trifasciatus - Threestripe/Three-lined pencilfish
Nannostomus unifasciatus - Oneline pencilfish

All Nannostomus spp. are legal imports to Australia as of 20/10/2013:
http://www.environment.gov.au/biodiv...mport-list.pdf

The IUCN Red List reports Nannostomus rubrocaudalatus as a species which has not yet been assessed at 20/10/2013:
http://www.iucnredlist.org/search

It is very important not to release any aquarium specimens into our waterways. Any that are not sold or re-homed/ given away, can often be re-sold to aquarium stores. If they are homed in ponds, care should be taken that they cannot escape in run-off into our waterways. Even if fish are native & local they should not be moved from one waterway to another, as this can transfer disease. If they are not local fish, they can both spread disease and either out-compete or eat local fish, shrimp & plants, causing their demise.

They are a good fish for people with some experience (beginners +1).

Relevant threads:
Diet:
http://www.aquariumlife.com.au/showt...ht=nannostomus

Video, keeping/treating with tea-tree & other advice:
http://www.aquariumlife.com.au/showt...ht=nannostomus

Video of males sparring, keeping with shrimp:
http://www.aquariumlife.com.au/showt...ht=nannostomus

Breeding:
http://www.aquariumlife.com.au/showt...ht=nannostomus