This article is about how to breed and keep Corynopoma riisei, the Swordtail Characin. The Swordtail Characin is a small silvery fish that rarely grow longer than 8 cm. It is a non-aggressive fish, highly suitable for a peaceful community aquarium. If you want to add some activity to your aquarium, Corynopoma riisei is a great choice because these fishes spend a lot of time playing with each other and darting around looking for food.
The Swordtail Characins hail from the Meta River basin and coastal rivers in Venezuela and Trinidad. The preferred water temperature is 22-26 degrees C. Keep the water hardiness below dH 25 and the pH-value in the 6.0-7.8 range. The Swordtail Characin is a schooling species and you should get a least 10 specimens, preferably more.
The breeding aquarium does not have to be large; a 5 gallon aquarium will give your Swordtail Characins plenty of space to breed. The aquarium should be densely planted along the sides and have an open area in the middle. Keep the water slightly alkaline, between pH 7.2 and 7.4. The water temperature should be somewhat higher than normal; 25-26 degrees F is recommended. Give your Swordtail Characins plenty of live food, such as worms and fruit flies.
During courtship, the male Corynopoma riisei may stroke the female using a spiny extension located at the gill cover. He can also stay in front of her and try to show off, flashing his spatula. Unlike many other egg-laying species, the male will fertilize the eggs while they are still inside the female instead of releasing his sperm into the water. The eggs will hatch within 48 hours.
Newly hatched Corynopoma riisei fry are small and silvery and will stay hidden among the plants. Well-fed female Swordtail Characins are not known to eat their eggs, but it can be a good idea to remove her when the fry has been hatched. The male can be removed directly after spawning. Liquid fry food and micro worms are suitable first foods for Swordtail Characins fry. When they are about one week of age, you can start giving them newly hatched brine shrimp. Older fry can be given larger brine shrimp, fat-free beef heart and high-quality flake food.
Swordtail characin fry have a silvery coloration with metallic blue, orange and pink shades. On the caudal fins, you can see light yellow rays. Swordtail characin fry form large schools in the aquarium and are known to school with similarly sized fry form other species.