Blue Striped Rivulus Killifish (Rivulus Xiphidius, Laimosemion xiphidius) Fish Species Profile
The Blue Striped Rivulus is a relatively small unique looking, peaceful and seclusive species of Killifish. These fish would fair better in a species only tank; however, the males should be given plenty of space to set up territories as they do not tolerate each other too well.
The Blue Striped Rivulus is best kept as either a pair or in small groups making sure you have on average one male to three or four females.
These Killifish are excellent jumpers, so a tight-fitting lid is essential.
The Blue Striped Rivulus has an elongated body with a rounded caudal fin.
A thick black stripe runs the length of the fish from just behind the eye through the caudal fin. They also display an iridescent blue line that borders above the entire black band. The rest of the tail is bright orange. The same pattern seen on the tail is also found in the anal and pectoral fins. Females are heavily spotted with light blue and display a relatively distinct dark line running the length of the body.
|Scientific Name||Rivulus Xiphidius, Laimosemion xiphidius|
|Other Names||Black-Tailed Rivulus|
|Aquarium Level||Middle - Top|
|Difficulty||Beginner - Intermediate|
|Best kept as||Pairs|
|Lifespan||2 - 4 years|
|Maximum Size||up to 4.5 cm|
|Temperature||73 - 77 ℉ (22.8 - 25 ℃)|
|PH||5.5 - 7.0|
|GH||2 - 6|
Origins of the Blue Striped Rivulus Killifish
The Blue Striped Rivulus is endemic to Surinam in French Guyana and Brazil in South America. They inhabit small slow-flowing creeks, rivers, brooks and streams that are shaded and has very soft, acidic water that is stained brown in tannins from decaying matter on the substrate.
The Blue Striped Rivulus can be relatively tricky to feed as they prefer eating live and frozen foods such as insect larvae, crustaceans, daphnia and live worms. Some killifish keepers do however manage to get their fish to eat dried products such as flakes and tubifex. It would be best if you took care not to overfeed them because live and frozen food is very rich.
Sexing the Blue Striped Rivulus Killifish
The difference between male and female Blue Striped Rivulus is relatively apparent. Males are larger and much more vibrantly coloured than the females whereas females are smaller and duller and possess spotting rather than a solid colour.
Breeding the Blue Striped Rivulus Killifish
It is relatively easy to breed Blue Striped Rivulus, and they become sexually mature around 10 to 12 months.
It is recommended that you should spawn this species in trios, but yield tends to be lower when bred this way, probably because the fish that are not spawning is probably consuming some of the eggs.
Many breeders do not use filtration in killifish breeding setups, but using a small, air-powered sponge filter to limit stagnation is a good idea. Water should be slightly acidic with a somewhat higher temperature. Keep the tank unlit, and remember peat filtration is beneficial.
It would be better if you condition the fish on a varied diet of live and frozen foods and keep the two sexes apart in separate conditioning tanks.
Please choose the best male and the plumpest female before placing them in the spawning tank. This method will allow females to recover between spawnings.
The fish will deposit their eggs in either bunches of fine-leaved plants such as java moss, in spawning mops or a layer of peat moss on the bottom of the tank. Alternatively, you can have a bare-bottomed tank with the spawning mediums. This setup will make egg collection or maintenance a lot easier.
If water conditions are right and the fish are well conditioned, spawning should present no specific problems. You can leave the eggs in the aquarium to hatch with their parents; however, some may get eaten.
If you want to maximise the yield of fry, you should remove the eggs.
Six to twenty eggs are usually deposited daily for around two weeks, and you should remove these gently as soon as you notice them.
It would be better if you only allowed breeding pairs to spawn for around a week or so before returning them into the conditioning tank as the spawning process takes a toll on the fish, especially the female. They can become weak and tired if left for too long.
Once removed, you can incubate the eggs either by placing them on a damp layer of peat moss in a small container or leaving them in the water. Fewer eggs tend to fungus if you keep them in the water, although you should still remove these fungus eggs as you notice them.
If incubating in water, you can transfer the eggs to a small aquarium or container containing water from the spawning tank. A few drops of methylene blue is prudent as this helps to keep the eggs in good condition. It would be best if you kept the aquarium or container under darkness as the eggs are susceptible to light and you will need to check the eggs daily for fungus eggs, which should be removed with a pipette. The eggs will hatch around 12 to 16 days later, depending on the temperature.
If hatching on peat moss, place the container in a warm, dark place and leave it for about 18 days, after which the eggs will be ready to hatch.
If you are producing various offspring, it is a great idea to label each container with the date, hatching date, species and the number of eggs to limit any disasters.
You can usually induce hatching of the egg by placing them in the raising aquarium after 18 days, where the wetting of the eggs spurs hatching. If this is unsuccessful, blowing gently into the water through a straw or a piece of an airline can trigger hatching.
The fry is miniature, and it would be best if you gave the fry infusoria as their first food being careful not to overfeed them and make sure you remove and replenish freshwater diligently daily.
When using the peat moss incubation method, the rearing tank can be 'seeded' a few days before hatching by adding a couple of drops of green water or liquifry.
After a few days, the fry will be large enough to move on to microworm and newly hatched brine shrimp. Two weeks after that, you can then introduce them to live and frozen varieties.
You should initially keep the water shallow, but as they grow, you can increase the level. Ultimate care must be taken regarding water quality in the rearing tank as the fry are very susceptible to velvet disease, so small water changes every 2-3 days is ideal for the best growth and condition.
The fry takes a considerable amount of time to grow for the first few months.