Many of the mid-water fishes mentioned in this next section tend to be fish who school in groups of eight or more. Many of these mid-water swimmers belong to the groups of fishes referred to as the cyprinids and the characins. With this being the case, you should consider only one or two species of schooling mid-water fish.
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1. Rosy Barb (Barbus conchonius)
- Origin: Northern India
- Size: 3 inches
- Food: Omnivorous
- Temperature: 64-72°F
The rosy barb is a very peaceful species that adapts well to a community aquarium. But it prefers cooler water than other community fish. In cooler waters, it is generally more colorful. Barbs get their name from the small barbels that act as sensory organs near and on their mouths. They are fast and agile and contribute great vitality to the mid-waters of the tank. Barbs, however, can cause harm to smaller fish and to fish with ornate finnage.
The tiger barb Barbus tetrazona is a related species. Do not introduce these fish singly or by pairs. They tend to be wild and disruptive, and even downright aggressive. But, if you keep them in schools of eight or more, they tend to establish a hierarchy within the school and will ignore the rest of the tank. It is recommended that schools contain both the more colorful males and the heavier females. Unlike the rosy barb, these Indonesian fish prefer warmer waters in the range of 68-79°F. The ruby barb, Barbus nigrofasciatus, is also a peaceful addition to the tank in much the same way. Originally from Sri Lanka, the ruby barb also prefers warmer water and the company of other barbs.
2. Red Rasbora (Rasbora heteromorpha)
- Origin: Southeast Asia
- Size: 2 inches
- Food: Omnivorous
- Temperature: 72–77°F
This rasbora is another popular fish that is better off in a school of eight or more. The red rasbora has a deeper body than its close relative, the red-striped rasbora, Rasbora pauciperforata, which is streamlined in shape. Red-striped rasbora grows about an inch larger and has similar temperature preferences. They, too, are better off in groups of eight or more. Egg-laying species of rasboras are not as easy to breed as the barbs, but they are extremely peaceful.
3. Neon Tetra (Paracheirodon innesi)
- Origin: Peru
- Size: 1.5 inches
- Food: Omnivorous
- Temperature: 68–79°F
The neon tetra is certainly one of the most popular fishes included in community aquariums. Two of the main reasons for their popularity are their exciting colorings and their hardiness. They are capable of tolerating a wide range of temperatures, which makes them very desirable. Like other mid-water fish, the neon tetra should be kept in a school of six or more individuals. The iridescent coloration of this fish will glow if the tank is properly lighted.
Two related tetra species include the cardinal tetra, Paracheirodon axelrodi, and the glowlight tetra, Hemigrammus erythrozonus. They will travel in schools peacefully throughout your aquarium.
Another ideal community fish is the black neon tetra, Hyphessobrycon herbertaxelrodi. It has a stouter body than the neon tetra. Read more about the Neon Tetra.
4. Angelfish (Pterophyllum scalare)
- Origin: Central Amazon to Peru, Ecuador
- Size: 6 inches
- Food: Omnivorous
- Temperature: 75-82°F
The angelfish is certainly one of the most exotic and recognizable fish in all the community aquarium world. However, angelfish are not for the beginner. You should have a well-established aquarium and be experienced if you want to take the step towards keeping these fish. They cannot withstand extreme fluctuations in water quality and temperature. These placid fish require tall decorations (like plants), which they will stay quietly among. They are best kept in small groups of four to six with other even-tempered fish such as neon tetras and black mollies. The angelfish is actually a cichlid. Surprisingly, they are probably the only ones of this species that have a somewhat peaceful disposition. When they grow to full maturity, approximately six inches or more, they will eat smaller fish. There are many varieties of angelfish.
5. Blue Gourami (Trichogaster trichopterus)
- Origin: Southeast Asia to Indo-Australian Islands
- Size: 4 inches
- Food: Omnivorous
- Temperature: 72-82°F
The blue gourami and its relatives are peaceful labyrinth fish. They do not need to be kept in schools but are quite well known to be happy in pairs. They have elaborate finnage and beautiful colors. They should not be included with fin nippers, like tiger barbs. Although listed here as mid-water fish, the gouramis will swim among the bottom decorations as well as make frequent excursions to the surface.
Included among gouramis are the dwarf gourami, Colisa lalia, the snakeskin gourami, Trichogaster pectoralis, and the pearl gourami, Trichogaster leeri. These fish are egg-layers. They build bubble nests during spawning like other labyrinth fish. The paradise fish, Macropodus opercularis, closely resembles the gouramis. The paradise fish is also a very hardy fish and can tolerate temperatures down to 61°F. Warning, this species may cause trouble. It may annoy, nip, or threaten other community species if they are very slow. Don’t put two males in the tank, as they will fight bitterly.
6. Glass Catfish (Kryptopterus bicirrhis)
- Origin: Eastern India and Southeast Asia
- Size: 4 inches
- Food: Carnivorous
- Temperature: 72-79°F
The glass catfish is one of the few catfish species that does not hang out on the bottom. This fish likes to school in groups of four or more. The glass catfish has a transparent body, so the internal organs can be seen. Although sometimes difficult to acclimate in the aquarium, this hardy fish is a worthwhile addition to the community tank. It’s better suited for a slightly more experienced aquarist.
