Rasboras are a companion group of slimmer cyprinids which offer a little extra in the way of color to the silvery danios, and although they can be speedy swimmers, they are usually a little more sedate in their movements around the aquarium. There are several deeper-bodied fish, and most of the genera occupy the middle and upper levels of the aquarium. Most reproduce in the egg-scattering manner. Like most cyprinids, the size of fish within the Rasbora genus varies widely, from less than 1 inch to over 3 feet. They may be distinguished from apparent near-related cyprinids by the absence of barbels, a whisker-like organ near the mouth found in some fish (notably catfish, loaches and and cyprinids).
Red-Line Rasbora (Rasbora pauciperforata), also called Red-stripe rasbora, is a charming fish that has an olive-green back and a silver belly. The sides of the body are light olive and there is a pinkish-red stripe present from the tip of the snout to the tail. The fins are relatively clear of color. This is a peaceful fish that prefers soft water and plenty of cover in which it can hide. It does well if it is kept with danios and hatchetfish. Flake food is readily accepted. Mayacca and Vallisneria plants should be present for breeding. Keep several fish to determine the pair and remove the rest.
Hi-spot rasbora, also called emerald eye rasbora is found in southeast Asia (malayan peninsula and Indonesia). The body is olive-brown dorsally and silvery-white in the belly region. The eye is bright emerald green that flashes bright green when it swims through areas of natural sunlight. It is a small fish that has a high dorsal fin with a large black spot on it. This is quite a shy species that should be kept in a group of three or more. It should not be housed with aggressive tankmates. Most aquarium foods are accepted provided that pieces are small enough for this fish to swallow. Crushed flake food seems to be a particular favorite for this species.
This species demands special treatment. The tank should be well planted around the sides and back, with an open space in front. The bottom should be dark. This fish loves sunlight and strut around it like butterflies. Spawning takes place in bundles of bushy plants. The pair should be well fed before being put out to spawn, because the females are very fond of eating their own eggs.
Exclamation-Point Rasbora (Rasbora urophthalma) is one of the small rasboras easily recognized by the horizontal stripe which is at its widest below the beginning of the dorsal fin and then narrows down to the point toward the tail base. This fish and the other small rasboras require a well-planted aquarium or it may turn out to be very shy. Spawning may be accomplished in a small aquarium which should be planted with 1 or 2 broad-leaved plants like Cryptocoryne species and a bunch of fine-leaved plants like Myriophyllum.