The Dwarf Pencil Fish, the Green Rivulus and the Hunchbacked Limia could be three freshwater fish in your tank. Find out about their behavior, what they look like, water conditions, how to feed them and how to breed them.

Dwarf Pencil Fish – Nannostomus marginatus (Family: Lebiasinidae)

Behavior:
It is a bit timid and likes its fellow dwarfs so its better to have few of them in your aquarium. They will grow to about 3 cms when adult and are slow swimmers so you will have plenty of time to admire them!.

Water and Tank Conditions:
This shy fish will need sheltered areas so make sure there is a well planted area and also a good amount of free space for it to swim around in. Ideally the water should be at about twenty four degrees Celcius.

Features and Colors:
It is not easy to tell the differences between the sexes. The males are thicker than the females and more brightly colored. The fish has three stripes running laterally along its flanks. Dark brown bands are located above and below the central gold one. The back is a golden brown with the body browny gray.

The fins are red around the perimeter and the bottom parts are also red. The Nannostomus genus has a unique characteristic in that its lateral bands change if they get frightened or at dusk. They change to stripes that slope instead.

Feeding:
This fish will eat a wide range of foods but due to its small mouth ensure the food size is sufficiently small.

Breeding Conditions:
Like the Croaking tetra the pencil fish does not readily breed. A shallow depth of slightly acidic water, about 12 cms, is needed for the breeding tank and a temperature of about 24 degrees centigrade. Ideally you would have breeding trap and the female will be mated with two males.

Remove the fish once spawning has taken place. Deposited eggs will be found all over the place. It will be a couple of days before the fry hatch. After hatching the fry can be fed on infusoria to start with, then fine dry food and when they get bigger flaked foods, daphnia and micro-worms.

Green Rivulus – Rivulus cylindraceus (Family: Cyprinodontidae)

Behavior:
The green rivulus is a hardy fish, peaceful and good at leaping so keep the cover on! It is is regarded as a bit of joker in the fish world due to its habit of taking up unusual positions and maintaining them for a while. It is best to keep these with fish around the same size.

Water and Tank Conditions:
Plant wise, a mixture of both submerged and floating varieties are needed. For the water, an average temperature of about 22 degrees centigrade will be alright although it can tolerate a fairly wide range.

Features and Colors:
The green rivulus, as its name suggests, is olive-green with spots that are darker green. It also has reddish spots near the back end. This fish is also called the cuban rivulus.

There are many species seen in aquariums from this genus and they all differ in color but their behavior and main features are the same. In particular they all have a ‘false eye’, which is in fact a spot located near the upper part of the peduncle fin.

Other species you will come across are the eye spot or ocellated rivulus (Rivulus ocellatus), the herring-bone rivulus (Rivulus strigatus), the yellow banded rivulus (Rivulus xanthonotus), the fire-tail rivulus (Rivulus milesi) and Hart’s rivulus (Rivulus harti).

Feeding:
You will notice how these fish become more a lot mmore lively when they are about to be fed. In general they are not fussy about the food they are given.

Breeding Conditions:
The difference between male and female is easy as the female has the large rivulus spot and is not as brightly colored compared to the male. A thickly planted breeding tank at 26 degrees centigrade is required with two females for each male.

They breed easily and once the eggs have been scattered about, take the plants and fertilized eggs to a separate incubation tank. Give it up to fourteen days for the eggs to hatch and feed the fry with infusorias for the first seven or so days.

Hunchbacked Limia – Poecilia nigrofasciata (Family: Poeciliidae)

Behavior:
Also known as the Humpbacked limia and the Black-barred limia. They are a peaceful fish and the females will grow to a bit more than 6 cms. The Poecilia caudofasciata species is smaller and the male and female reach lengths of about 4 and 6 cms respectively.

Water and Tank Conditions:
twenty four degrees Celcius is adequate.

Features and Colors:
They are called hunchbacked because the young fish exhibit an arched back, which becomes greater as they age. The other parameter that also changes with age is the color. Young ones have a yellow belly, dark vertical stripes and an overall olive color.

The older fish has iridescent green spots on the bands, the stomach has a dark border, the dorsal fin is bigger with spines becoming black. As in a lot of cases the female is duller than the male, color wise, not personality wise!

Feeding:
The main diet for the Hunchbacked limia is algae and other vegetable matter with the odd live meal thrown in (literally!).

Breeding Conditions:
Standard procedures for live-bearing fish should be followed but note that the fry are less easy to raise than usual and one tip is to put the breeding tank in a location where natural sunlight will fall upon it.

Now you can have three additional freshwater fish to put in a tank and look after. Just make sure that you have enough tank space to cater for your new additions.

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