The splash tetras belong to the same family as the pencilfishes. Unfortunately the majority are rarely deliberately imported for the aquarium trade but do turn up occasionally in shipments of other fishes. The only one seen on a fairly regular basis is Copella arnoldi (Splash tetra, Jumping characin), the fish that gives the group its common name. A fairly unassuming fish to look at, males are larger, growing to 8 cm (3 1/4 in), and have more colour in their finnage than females, 6 cm.
Copella arnoldi (Splash tetra, Jumping characin) is a good community fish which inhabits the mid-to upper layers of the aquarium. If possible, keep a group, or if not, a pair, as their main attraction is their unusual method of reproduction. Water conditions are not critical: keep the hardness below 12 dH and the pH around neutral (so most community aquaria with plenty of plants will suit this fish). Regular partial water changes are essential to keep them healthy. If they become listless or hide all the time this usually indicates a slight deterioration in water quality. A partial water change will rectify the situation.
Copella arnoldi (Splash tetra, Jumping characin) will jump to catch food and also when breeding. The addition of floating plants such as Indian fern (Ceratopteris thalictroides), and the provision of a good cover glass, will ensure that they do not leap to their deaths. Feeding is not a problem as they accept flake, frozen, and live foods, but to condition them for spawning, offer plenty of live and frozen invertebrates such as Daphnia, bloodworm, and mosquito larvae; preferably live.
Breeding Splash Tetras
Place a pair in a small breeding tank (this need be only about 50 cm (18 in) long), using water from the main aquarium, and make sure that you have some broad-leaved plants such as Echinodorus sp. (Amazon sword plants) whose leaves reach just above the water surface. Place a tight cover glass over the aquarium and make sure the water level allows a small gap between the water surface and the cover glass.
When ready, the pair will swim together and then jump. Pressing their bodies close together and turning belly-up, they deposit a few eggs on the underside of a leaf or on the cover glass. This all happens in a split second and is repeated many times, with eight to ten eggs being deposited on the chosen site at each jump. By the end of spawning there will be a clutch of up to 200 eggs. As these are above the water, the male tends them, splashing water over them every 30 seconds or so, hence the common name. If unfertilized eggs fall off the leaf/cover glass the male ignores them. The eggs hatch after about 60 hours and the fry drop into the water. It takes another 36-48 hours for the fry to absorb their yolk sacs, after which they require small foods such as newly hatched brine shrimp.
Other members of the genus may also be kept in the community aquarium, but their method of breeding is “normal”. After conditioning, the pair spawn on a pre-cleaned leaf and the male tends the eggs, which hatch in about 30-36 hours. The fry require fine foods such as infusoria followed by newly hatched brine shrimp.
Copella guttata (Red-spotted characin), a much larger fish (growing to 15 cm (6 in)), places its eggs in a depression in the substrate. Again, the male guards the eggs. On hatching, they should be raised in the same way as the other species.