The so-called Red Minor tetra is most likely the
Serpae Tetra in our profiles; common names can be confusing, the scientific is
Hyphessobrycon eques. The dorsal fin of the male is almost a solid black, whereas this fin on the female lacks the black in the lower part; as with most tetra, the female is rounder (thicker in body) than the male.
For spawning, here is some info from Matt Ford, a biologist, taken from his site Seriously Fish:
You'll need to set up a separate tank if you want to raise decent numbers of fry. Something around 18" x 10" x 10" in size is fine. This should be very dimly lit and contain clumps of fine-leaved plants such as
Java Moss or spawning mops, to give the fish somewhere to deposit their eggs. Alternatively, you could cover the base of the tank with some kind of mesh. This should be of a large enough grade so that the eggs can fall through it, but small enough so that the adults cannot reach them. The water should be soft and acidic in the range pH 5.5-6.5, gH 1-5, with a temperature of around 80-84°F. Filtering the water through peat is useful, as is the use of RO water. A small air-powered sponge filter bubbling away very gently is all that is needed in terms of filtration.
It can be spawned in a group, with half a dozen specimens of each sex being a good number. Condition these with plenty of small live foods and spawning should not present too many problems.
Alternatively, it can be spawned in pairs. Under this technique, the fish are conditioned in male and female groups in separate tanks. When the females are noticeably full of eggs and the males are displaying their best colours, select the fattest female and best-coloured male and transfer them to the spawning tank in the evening. They should spawn the following morning.
In either situation, the adults will eat the eggs given the chance and should be removed as soon as eggs are noticed. These will hatch in 24-36 hours, with the fry becoming free swimming a 3-4 days later. They should be fed on an infusoria-type food for the first few days, until they are large enough to accept microworm or brine shrimp nauplii. The eggs and fry are light sensitive in the early stages of life and the tank should be kept in darkness if possible.