Porthole Rasbora (Rasbora cephalotaenia)
The Porthole Rasbora is a lesser-known species in the aquarium trade. However, they are peaceful, active and hardy fish that make an excellent addition to a friendly community aquarium of Southeast Asian or Indian fish species.
Porthole Rasboras are a sociable species in nature, so it would be better to keep them in groups of 6 or more individuals. This is because these fish are less nervous and display better colours in the company of their own kind.
Suitable tankmates for these Rasboras could include similarly sized Rasboras, Loaches, peaceful Barbs and Gouramis. These fish are very active and require an aquarium with plenty of swimming space; therefore, it is advised that you have an aquarium that is no smaller than 255 litres.
Porthole Rasboras thrive in biotope aquarium setups. They require soft, sandy substrate with driftwood tangles and roots, plenty of shaded areas, dried leaf litter, peat, and dim lighting. Tannin-stained waters from wood and decomposing detritus are ideal.
Porthole Rasboras are a robust species that can reach up to 13 cm in length; they have silver bodies that, in a certain light, can appear a pinky blush colour. Their bodies also display dark dots resembling a horizontal line. Their fins are yellowish-orange.
|Scientific Name||Rasbora cephalotaenia|
|Origins||China, Laos, Vietnam|
|Aquarium Level||Middle - Top|
|Difficulty||Beginner - Intermediate|
|Best kept as||Groups 6+|
|Lifespan||3 - 5 years|
|PH||5.0 - 7.5|
|GH||1 - 12|
|71 - 79℉|
21.7 - 26.1℃
Photos of the Porthole Rasbora
Porthole Rasboras can be found in the Thu Bon River in central and northern Vietnam, the Pearl River basin in southeastern China, the Nam Ma River basin in Laos, and they also occur in the Nandujiang and Wanquanhe River on Hainan Island.
These Rasboras inhabit small to medium rivers and streams with slow running blackwater but can sometimes populate rice fields, canals and ditches.
The water in their natural habitats is often stained brown due to the freeing of chemicals and tannins released by decomposing organic matter. The substrate is usually covered with fallen leaves, twigs and branches and these settings contain very soft, acidic water and are often somewhat dark due to the forest cover above.
What to feed the Porthole Rasbora
Porthole Rasboras are unfussy and relatively easy to feed. However, for the best condition and colour of your fish, it would be better to offer them frequent meals of small live and frozen foods such as daphnia, brine shrimp, mosquito larvae, cyclops and bloodworm. You will also need to provide these fish with good quality dried food such as crushed flakes, micropellets and granules to balance their diet.
How to sex the Porthole Rasbora
It is somewhat difficult to distinguish the males from female Porthole Rasboras. However, Mature females appear to be rounder in their stomachs and often a little larger than the slimmer, smaller males.
How to breed the Porthole Rasbora
Like most Cyprinids, Porthole Rasboras are an egg-scattering spawner that presents no parental care. However, if your fish are in good health, they will produce often. In a densely planted, established aquarium, small numbers of fry may start to appear without human interference.
However, if you would like to increase fry numbers, a more controlled approach will be required.
You can condition an adult group together, but you will need to set up a separate breeding tank. It would help if you dimly lighted this tank, left the bottom bare, or covered it with a big enough mesh to allow eggs to fall through but small enough that the adults cannot reach them. You can also use artificial grass type matting; this can work just as well.
The water itself should have a slightly acidic to neutral pH, and the temperature needs to be somewhat higher than their regular aquarium. You can initially add an internal power filter, which should be positioned so that the flow is directed down the entire length of the tank.
Once the adult fish are well-conditioned and the females are noticeably full of eggs, you should introduce one or two pairs Into the breeding tank. You can encourage spawning by adding small amounts of cool water every few hours so that the tank is slowly topped up and feeding them small amounts of live and frozen foods. Several spawning situations will more than likely occur before a female has run out of eggs.
If the couples fail to spawn straight away, you can leave them where they are. However, if you do not notice any eggs after 3 or 4 days, you should return them to their usual aquarium and choose another pair.
Once all the eggs have been laid, you will need to remove the adults from the breeding tank as soon as possible; otherwise, they will consume the eggs if given a chance.
The incubation period is temperature-dependent; however, the eggs will usually hatch somewhere between 18 and 48 hours later, with the young becoming free-swimming 24 to 48 hrs after that.
It would be best to initially feed your fry with Paramecium or similar, moving on to baby brine shrimp and microworm once your fry are large enough to accept them.