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Description: H. melanistium from Essequibo, Guyana, attains a length of 5– 6 cm. Body colouration light grey covered with small dark spots. Black line extending from forehead down through the eye. A golden coloured saddle adorns area from back of eye to dorsal. Front part of dorsal fin is black extending into the top of the fishes back. (H. melanistius melanistius and C. melanistius brevirostrus are sub species of Hoplisoma melaniseum).

Maintenance: My five H. melanistiumconsisted of two female and three males, which were  housed  in an 18"x12"x12" tank. Filtration Bio-foam 45 sponge plus small box filter, both air-driven. Decoration included a glass trough which was filled with fine gravel and  planted with Java fern, Java moss and Hygrophila. This was positioned at one side of  the tank. Water conditions were pH 6.5 temperature 24C / 76F with weekly 25% water changes.

Feeding: Frozen bloodworm, black mosquito larva, mysis shrimp and various good quality dried foods. I don't feed live foods to any of my fish. Having maintained the cory’s as described above for quite sometime, they were now in breeding condition. The process of a possible spawning was about to begin. Between 18th May and 14th June a total of 7 out of 10 spawning's resulted successfully with fry. Eggs laid in one spawning ranged from 25 to 71. It  was turning into a small production line until I exhausted my stock of small tanks. I began leaving the eggs with the parent’s and was pleased to find that they do not eat their eggs or fry. These young appeared to grow bigger and faster when left with the parent's.

Breeding: First spawning occurred 6 days after I carried out a 50% water change straight from the household supply pH7. This dropped the temperature by several degrees. First spawning occurred six days later. The spawning female places her eggs 1" below the water surface, she never placed any eggs on plants. 46 eggs were laid which I removed and placed into a small tank containing water from the breeding tank. One drop of methylene blue was added and light aeration to maintain water circulation. Hatching 5 days later, a further 2 days and the fry were free swimming. These were fed alternative feedings of microworm culture and newly hatched brine shrimp. Water changes every day using water from breeding tank.

As the fry progressed they were moved to larger tanks with sponge filtration. On one occasion while carrying my usual weekly water change in the breeding tank I was called into the house. The tank had been left with a 25% water reduction. I returned one hour later to find that they had spawned.

Since this article was first written in 1995. I understand that the Local Authority Water Board have come into line with EEC regulations. This has drastically altered pH conditions which was up until then pH7 and is now pH 8.3, which is bad news for many species, we as hobbyists maintain.

 

Image © Ian Fuller @

 

Lineage: Placed in Lineage 9, the "short-snouted" species with the designated type species: C. punctatus. A revision in the future would constitute the resurrection of the genus name Hoplisoma (Agassiz, 1846).

As of the latest revision (Dias et al 2024) Corydoras melanistius has now been placed in Lineage 9 and has the new genus name of Hoplisoma and a change to the specific name to melanistium.