Rachovia splendens

 RACHOVIA SPLENDENS

 Originally published as: B.K.A. Leaflet No.71 June 1971

Habitat: Temporary ponds and ditches.

Size: Up to 2.5″

Description: Male: One of the more colourful South American killies. The flanks are a beautiful dark green, shading to brown on the head and back. Each scale is outlined in brown, forming a network over the body. The unpaired fins are green, with a darker, usually black, outer edge. The caudal develops, with age, quite long but often ragged extensions. These are sometimes absent, and in any case rarely appear before the sixth or seventh month of age.

The pectorals are grey to black, and the ventrals are a lighter green, sometimes yellowish.

Over all these colours is a blackish sheen, emphasised by certain light conditions and when the fish are excited. When kept over dark peat the fish are usually black all over.

            Female: A colourless fish, light brown with a few slightly darker spots and markings, especially in the unpaired fins. She is very reminiscent of a female guppy, but lighter coloured.

Care and maintenance: These fish, living in the wild in water, which is often polluted by decaying vegetation, are very hardy, and will tolerate conditions which will often harm less robust fish. Normally, they are happy in soft, acid water, but will live happily in hard and/or alkaline water provided the change is not sudden.

They are mainly carnivorous and will do well on all the normal live foods. White worm, if fed frequently, may cause them to become sluggish and fat; plenty of earthworm, daphnia and mosquito lavae suit them well.

Temperature tolerance covers a wide range, and I have kept these fish at between 64-82F. (18-28C.) without noticing distress at either extreme. Aeration is not necessary. A small tank, say 10″ x 6″ x 6″ is adequate provided there is sufficient cover for the female(s).

Breeding: So far as is known, these fish are true annuals, that is, they inhabit waters which dry up during the dry season leaving the eggs to incubate in the almost dry mud until the next wet season. Water incubation of these eggs is not successful; the eggs remain clear and eventually (6-12 months) disintegrate.

Spawning takes place in peat or mulm at the bottom of the tank. If the base of the tank is clear, the fish will spawn on the bottom glass; if provided with a deep layer of peat they will dig to a depth of up to three inches to spawn.

Eggs are quite large and numerous. They are almost colourless but with a slight amber tint. They should be stored in almost dry peat; with luck, some of the eggs will be fully developed in not less than 15 weeks. These may be recognised by the eyes shining through the wall of the eggs. If such developed eggs are placed in shallow water, they will hatch in 24 hours.

Unfortunately, resting eggs are very common. These are a natural form of insurance against a freak early wet spell causing all the fry to hatch before the true wet season, only to perish as the pond dries up again before the fish are old enough to spawn and perpetuate the species. Such eggs may not develop for well over 12 months. Wetting these eggs and then redrying after a week may hasten their development, but this is not guaranteed.

The fry, when they do finally condescend to emerge, are quite robust and well able to eat newly hatched brine shrimp or micro worms. Growth is quick and the fish should be sufficiently well developed to spawn in six weeks. If a large number of belly sliders are noticed, probably the peat in which the eggs were stored was too wet; I must emphasise that these eggs need almost dry peat.

Males tend to squabble and tear each other’s fins, so are best kept apart as they mature. Females may, if not ready to spawn, be harmed by the very active males.

General: A very desirable fish, needing no more attention than most killies. The irregular hatching and comparatively long incubation may make them rather difficult to obtain for some time to come, but this is a species well worth looking out for.

References:
https://www.itrainsfishes.net/content/rachovia_splendens_001.php