What fish can live with Rainbow / red-tailed black shark?

Pair with mid- and top-zone fish (rainbowfish, danios, larger tetras, gouramis). Avoid red-tailed sharks, other rainbow sharks, slow long-finned fish.

What tank mates should you avoid with Rainbow / red-tailed black shark?

Avoid Betta, Chili Rasbora, German Blue Ram based on size, temperament, or predation risk on file.

What size tank do Rainbow / red-tailed black shark need for a community?

150 L minimum. Lateral length matters more than the litre figure; a long footprint cuts aggression sharply.

Rainbow / red-tailed black shark tank mates

Dark body with bright red fins, bottom zone. Calm as a juvenile, then territorial as it matures, and will fight other rainbow sharks to the death.

Evidence: partially verified

Confidence: high

Lists below are built from this species record (safest, best with, risky, unsafe) — each link opens a pair-level check, not a guarantee.

← Full Rainbow / red-tailed black shark profile·Compatibility checker·Tank builder·More barb

Best tank mates (on file)

Merged from conservative safest and best with fields — de-duplicated by species.

Bala / silver shark Pair check
The Rainbow / red-tailed black shark profile lists Bala / silver shark as both safe and a recommended pairing. Bala / silver shark schools in groups of 5 or more, so plan room for the whole group rather than one fish. Bala / silver shark grows bigger than Rainbow / red-tailed black shark (35cm vs 15cm). Stock the Rainbow / red-tailed black shark group large enough to outnumber the Bala / silver shark, or the smaller fish ends up bullied or off food.
Boesemani Rainbowfish Pair check
The Rainbow / red-tailed black shark profile lists Boesemani Rainbowfish as both safe and a recommended pairing. Boesemani Rainbowfish schools in groups of 6 or more, so plan room for the whole group rather than one fish.
Corydoras Catfish Pair check
The Rainbow / red-tailed black shark profile lists Corydoras Catfish as both safe and a recommended pairing. Corydoras Catfish schools in groups of 6 or more, so plan room for the whole group rather than one fish.
Dwarf Gourami Pair check
The Rainbow / red-tailed black shark profile lists Dwarf Gourami as both safe and a recommended pairing. Dwarf Gourami is a peaceful beginner-care species with a 60L minimum. Run the pair checker for your specific tank before stocking.
Giant danio Pair check
The Rainbow / red-tailed black shark profile lists Giant danio as a recommended pairing. Giant danio schools in groups of 6 or more, so plan room for the whole group rather than one fish.

Risky or situational

From risky tank mates and broad avoid with (excluding “unsafe” below). May work with species-only setups, more water, or mature systems — read the pair page.

Neon Tetra Open pair check
Marked risky or situational on the profile. Tank length and group size change the outcome more than a temperament label does.
Guppy Open pair check
Marked risky or situational on the profile. Tank length and group size change the outcome more than a temperament label does.
Angelfish Open pair check
Angelfish is flagged predatory. Equal-size adults usually coexist, but the moment one is stressed, sick, or smaller after a moult, it becomes prey. Both species defend territory. The pairing needs a long footprint and rockwork or planting that breaks the sightline between two defended spots. Angelfish is rated semi-aggressive, so expect chasing, fin damage, or display behaviour directed at Rainbow / red-tailed black shark. Run the pair checker before stocking.
Discus Open pair check
Temperature ranges barely overlap between the two, so one species ends up living at the edge of its comfort window. Run the pair checker before stocking.

Fish to avoid with Rainbow / red-tailed black shark

From the unsafe list — predation, aggression, or space rules on this profile.

Betta See why (pair)
Betta conflicts with Rainbow / red-tailed black shark on temperament, predation, or footprint. The juvenile size in a shop tank is not the figure that matters here.
Chili Rasbora See why (pair)
Chili Rasbora conflicts with Rainbow / red-tailed black shark on temperament, predation, or footprint. The juvenile size in a shop tank is not the figure that matters here.
German Blue Ram See why (pair)
German Blue Ram conflicts with Rainbow / red-tailed black shark on temperament, predation, or footprint. The juvenile size in a shop tank is not the figure that matters here.

Tank size and groups

Published minimum for Rainbow / red-tailed black shark: 200L — group minimum 1 .
Compatibility changes when the tank is too short for turning, too little for a real school, or too warm for one species and not the other — that is why pair checks include tank context, not only temperament.
Nearest litre hub to this minimum: 200L hub.

Easier alternatives to consider

Conservative beginner-peaceful picks from the library — not replacements for reading, but a shorter on-ramp than this species for a first tank.

Plan before you buy

Pair checks for every mix, then multi-species stocking in the builder.

Open compatibility checker Tank builder

Filtration & heating

A 200L minimum tank for Rainbow / red-tailed black shark needs a filter rated for at least 800L/hr turnover and a heater maintaining 24–28°C.

Filter buying guide →Heater buying guide →Beginner plants guide →