玫瑰魮脂鲤 · Rosy Tetra

Overview

The peaceful Megalamphodus rosaceus is supplied mainly by commercial farms. It feels more secure and shows stronger color in a sheltered group setting; sparse, exposed layouts often leave it shy and pale.

Distribution & habitat

It occurs in Guyana, Suriname, and Brazil, including the Essequibo, Corantijn, and Suriname systems. Forest tributaries with slow water are typical, often brown and acidic from decomposing organic material.

Aquarium setup

A small group needs a tank at least about 60 cm long. Sand, branches, roots, and dried leaves form a natural arrangement under subdued light. Replace old leaves periodically before they foul the water. A carefully maintained planted aquarium also works well, even though aquatic plants are not prominent in its typical natural waters.

Commercial stock tolerates a range of conditions, with acidic water generally bringing out better color.

Diet & feeding

Small invertebrates make up most of the wild diet. Captive fish are undemanding and can receive a mixture of flakes, granules, and small live or frozen foods.

Behaviour & compatibility

Keep at least six, preferably ten or more. Groups provide security, and several males produce attractive fin displays. Avoid very large or boisterous companions that dominate feeding. Mild small tetras, pencilfishes, dwarf cichlids, bottom-dwelling catfishes, and other suitably matched small species are possibilities.

Sexual dimorphism

Mature males have extended dorsal and anal fins and tend to be larger, slimmer, and more colorful. Females are fuller-bodied.

Breeding

Use a separate dim tank for better fry survival, with soft acidic water and gentle sponge filtration. Fine plants or mops provide spawning sites, while mesh can let eggs fall beyond adult reach. Groups of around six of each sex can be used. Alternatively, condition the sexes separately, then introduce a ripe female and brightly colored male in the evening for likely spawning the next morning.

Remove adults as soon as eggs are seen because they will eat them. Hatching takes approximately 24–36 hours, followed by another 3–4 days to free swimming. Begin with infusoria-sized food and progress to microworms and Artemia nauplii. Eggs and early fry are light-sensitive, so maintain darkness where practical.

Notes

The species closely resembles Megalamphodus bentosi and was once treated as its subspecies. Absence of the dark mark immediately behind the gill cover is a useful visible distinction.